“No Service” After Unlock on a New SIM? Run ThisĀ 12-Step Diagnostic Checklist

By Robiul Hossain
August 8, 2026
"No Service" After Unlock on a New SIM?

TL;DR ā€” The Honest Quick Answer

“No Service” after unlocking usually comes down to one of four things:Ā the unlock never fully processed on the carrier’s end, the new SIM was never activated, the APN settings are wrong, or the phone doesn’t support the new carrier’s bands.

Fastest fix path:Ā toggle Airplane Mode ā†’ restart the phone ā†’ confirm the unlock with your old carrier ā†’ confirm the new SIM is activated ā†’ set the APN manually ā†’ update carrier settings. That sequence solves the majority of cases in under 30 minutes.

If nothing works, the problem is almost alwaysĀ on the carrier’s sideĀ ā€” a stuck port-in or a SIM that was never provisioned. Call the new carrier, not the old one.

You did everything right. You waited out the lock period, got the unlock confirmation, popped in a shiny new SIM from your new carrier ā€” and the phone saysĀ “No Service.”Ā Or “SIM Not Provisioned.” Or it just spins on “Searchingā€¦” forever.

Here’s the good news: this problem is almost never a broken phone. In our experience helping readers switch carriers, “no service after unlock” traces back to a short list of causes ā€” and each one has a specific test. This checklist walks you through them in order, from the 30-second fixes to the “okay, time to call the carrier” steps.

Why this matters more in 2026

Unlock rules changed this year. In January 2026, the FCCĀ waived Verizon’s old 60-day automatic unlock rule. Verizon phones bought after late January 2026 now stay locked until they’re paid off ā€” so a phone youĀ assumedĀ was unlocked may not be. That’s why Step 2 below is more important than ever.

First: What Does Your Error Actually Mean?

Different error messages point to different problems. Find yours before you start troubleshooting ā€” it can save you half the checklist.

What Your Phone SaysMost Likely CauseJump To
“No Service” (bars are empty)Unlock incomplete, network not selected, or band mismatchSteps 1, 2, 5, 9
“SIM Not Provisioned” / “SIM Not Valid”New SIM was never activated by the carrierSteps 3, 7
“SIM Not Supported” / “SIM Locked”The phone is still carrier-lockedStep 2
Signal bars, but no data (calls work)Wrong or missing APN settingsSteps 4, 6
“Searchingā€¦” foreverNetwork selection stuck, or old network settings cachedSteps 1, 5, 8
“Emergency Calls Only”Phone sees towers but can’t register ā€” provisioning or IMEI issueSteps 7, 9, 10

The 12-Step Diagnostic Checklist

Work through these in order. Each step rules out one cause, so skipping ahead usually means backtracking later. Steps 1ā€“8 you can do yourself; Steps 9ā€“12 may need a phone call.

Toggle Airplane Mode, Then Restart

ā± 2 min
Yes, it’s the clichĆ© fix ā€” but it works so often that skipping it wastes time. Turning Airplane Mode on for 30 seconds forces the phone to drop its old network registration. A full restart then makes it re-read the SIM from scratch and search for the new carrier.
  • Airplane Mode ON ā†’ wait 30 seconds ā†’ OFF
  • Still nothing? Power the phone fully off (not just sleep), wait 15 seconds, power on

    • Confirm the Unlock Actually Went Through

    ā± 5ā€“10 min
    “Unlock requested” and “unlock completed” are two different things. Carriers process unlocks in batches, and some require a final restart (or connecting the phone to Wi-Fi) before the unlock applies to the device itself.
  • iPhone:Ā Settings ā†’ General ā†’ About ā†’ Carrier Lock. It should sayĀ “No SIM restrictions.”Ā If it says “SIM locked,” the unlock hasn’t applied yet.
  • Android:Ā Samsung and Pixel phones usually show a “Network unlock” or SIM lock status under Settings ā†’ Connections (or ask your old carrier to confirm by IMEI).
  • Verizon phones bought after January 27, 2026:Ā devices now stay locked until fully paid off ā€” automatic 60-day unlocking ended. If you financed the phone, check your balance first.
    • Under the industry’s voluntary unlocking standards, carriers must post their unlock policies and tell you when your device is eligible ā€” theĀ FCC’s cell phone unlocking pageĀ explains your rights and each framework in plain English.
    Common trap

    prepaid phones often have a longer lock period (typically 12 months) than postpaid phones. If you bought the phone as a prepaid device and only used it a few months, it may still be legitimately locked ā€” no amount of troubleshooting will fix that.

    Reseat the Physical SIM (or Check the eSIM Line)

    ā± 3 min
    A SIM that’s slightly misaligned in the tray can read intermittently ā€” enough to show the carrier name but not enough to register. And on eSIM, the number-one miss is simply that the new line isn’t turned on.
  • Physical SIM:Ā power off, eject the tray, wipe the gold contacts with a dry cloth, reseat, power on
  • eSIM (iPhone):Ā Settings ā†’ Cellular ā†’ confirm the new line is listed AND toggled on, and set as the line for cellular data
  • eSIM (Android):Ā Settings ā†’ Connections/Network ā†’ SIM manager ā†’ confirm the new profile is downloaded and enabled
  • If you kept your old carrier’s eSIM profile on the phone,Ā turn it offĀ ā€” two active profiles fighting for the data line causes exactly this symptom

    • Set the APN Manually

    ā± 5 min
    The APN (Access Point Name) is the address your phone uses to reach the carrier’s data network. Unlocked phones ā€” especially ones that came from another carrier ā€” often keep theĀ oldĀ carrier’s APN baked in. Result: bars show up, calls may even work, but data is dead.
  • iPhone:Ā Settings ā†’ Cellular ā†’ Cellular Data Network (if this menu doesn’t appear, your carrier pushes APN automatically ā€” skip to Step 6)
  • Android:Ā Settings ā†’ Network & Internet ā†’ SIMs ā†’ Access Point Names ā†’ add new APN
    • Enter the APN name from the table below, save it, select it, then restart the phone.
    Carrier / NetworkAPN ValueNotes
    T-Mobile (and most T-Mobile MVNOs like Mint, Metro)fast.t-mobile.com (Mint: wholesale)Leave username/password blank
    AT&T (and Cricket)phone or nxtgenphone (Cricket: ndo)AT&T also requires the device on its approved list ā€” see Step 9
    Verizon (and Visible)vzwinternetUsually auto-configured; manual entry rarely needed
    US Mobile / other multi-network MVNOsVaries by network assignmentCheck your account dashboard ā€” the APN depends on which network your line runs on
    Tip:

    APN values change occasionally and MVNOs sometimes use their own. If the values above don’t work, the carrier’s own APN support page is the source of truth ā€” search “[carrier name] APN settings” from their official site, not a forum.

    Select the Network Manually

    ā± 3 min
    Sometimes the phone is still trying to auto-register on the old carrier’s network. Forcing a manual scan makes it list every network in range ā€” and lets you pick the right one.
  • iPhone:Ā Settings ā†’ Cellular ā†’ Network Selection ā†’ turn OFF Automatic ā†’ wait for the scan ā†’ tap your new carrier
  • Android:Ā Settings ā†’ Network & Internet ā†’ SIMs ā†’ Automatically select network OFF ā†’ choose your carrier
  • Once you register successfully, turn Automatic back ON so roaming and tower handoffs work normally
    • If your new carrierĀ doesn’t appear in the scan at all, that’s a strong clue you have a band-support problem ā€” jump to Step 9.

    Update Carrier Settings and the OS

    ā± 5ā€“15 min
    Carrier settings are small config files that tell your phone how to talk to a specific network ā€” including 5G settings, VoLTE, and Wi-Fi Calling. A new SIM often triggers an update prompt, but not always, and an out-of-date bundle can block registration entirely.
  • iPhone:Ā connect to Wi-Fi ā†’ Settings ā†’ General ā†’ About ā†’ wait 30 seconds on that screen. If an update is available, a prompt appears ā€” tap Update. Apple explains the process in itsĀ carrier settings update guide.
  • Android:Ā Settings ā†’ System ā†’ Software update. Carrier config on Android ships inside system updates, so being even one update behind can matter with a new network.

    • Confirm the New SIM Is Actually Activated

    ā± 10 min
    This one catches a lot of people. An unlock problem and an activation problem look identical from the phone’s side ā€” but they’re fixed by different companies. If your SIM was never activated (or your number port got stuck halfway), no phone-side setting will help.
  • Log into yourĀ new carrier’sĀ app or website ā†’ check the line status. It should say “Active,” not “Pending”
  • Porting a number?Ā Ports from another carrier can take from a few minutes to 24+ hours. A wrong account number or transfer PIN silently stalls the port ā€” check for any “action needed” notice on your account
  • Test with the SIM in aĀ second unlocked phoneĀ if you have one. If it shows “No Service” there too, the SIM/line is the problem ā€” not your phone

    • Reset Network Settings

    ā± 5 min
    This wipes every cached network config ā€” old APNs, old carrier profiles, preferred network lists ā€” and forces a completely clean registration. It’s the deepest phone-side fix available.
  • iPhone:Ā Settings ā†’ General ā†’ Transfer or Reset iPhone ā†’ Reset ā†’ Reset Network Settings
  • Android:Ā Settings ā†’ System ā†’ Reset options ā†’ Reset Wi-Fi, mobile & Bluetooth
    • Heads up:Ā this also deletes saved Wi-Fi passwords and paired Bluetooth devices, so have your Wi-Fi password handy. It doesĀ notĀ delete photos, apps, or personal data.

    Check IMEI Compatibility and Band Support

    ā± 10 min
    “Unlocked” means the carrier lock is off. It doesĀ notĀ mean the phone speaks every network’s language. A phone built for one carrier’s bands can be perfectly unlocked and still get weak or zero coverage on another network ā€” especially international models, older phones, and carrier-specific variants.
  • DialĀ *#06#Ā to display your IMEI
  • Run it through yourĀ new carrier’sĀ official “Bring Your Own Device” (BYOD) checker on their website ā€” every major carrier has one
  • The checker tells you if the phone is fully compatible, partially compatible (voice but no VoLTE/5G), or not supported
    • AT&T is the strictest:Ā it maintains an approved-device whitelist, and phones not on it can be blocked from the network even when the hardware technically supports the bands.

    Rule Out a Blacklisted IMEI

    ā± 5 min
    If you bought the phone used, there’s one ugly possibility left: the IMEI is on the shared blacklist for being reported lost, stolen, or having unpaid financing. A blacklisted phone can be fully unlocked and still refuse to register on any U.S. network.
  • Use a free IMEI status checker (most major carriers’ BYOD checkers will flag this) or ask any carrier store to run the IMEI
  • If it’s blacklisted for unpaid balance by theĀ previous owner, the seller is responsible ā€” contact them or your payment platform’s buyer protection
    • Avoid “IMEI cleaning” services

    Sites promising to remove a blacklist flag for a fee are either scams or altering the IMEI ā€” which is illegal in the U.S. The only legitimate fix is resolving the issue with the carrier that flagged it.

    Test the Phone With a Different SIM

    ā± 5 min
    The final isolation test. Borrow a working SIM from a friend or family member (any carrier) and put it in your phone.
  • Their SIM works in your phoneĀ ā†’ your phone and unlock are fine. The problem is your new SIM or line ā€” go back to Step 7 and call your new carrier
  • Their SIM also shows “No Service”Ā ā†’ the unlock didn’t apply, or there’s a hardware issue (damaged SIM reader or antenna). Contact your old carrier about the unlock first; if confirmed unlocked, it’s repair time

    • Call the Right Carrier ā€” With the Right Info

    ā± 15ā€“30 min
    By now you know which side the problem is on. Call the right company and lead with what you’ve already tested ā€” it skips the first 15 minutes of scripted troubleshooting.
  • Call your OLD carrier if:Ā the phone still shows “SIM locked” / “Carrier Lock: SIM locked” (Step 2 failed). Ask them to confirm the unlock was pushed and request a re-push
  • Call your NEW carrier if:Ā the phone shows unlocked but the line is pending, the port is stuck, or “SIM Not Provisioned” persists. Ask them to verify the SIM’s ICCID is attached to your line and to re-provision it
  • Have ready: your IMEI (*#06#), the SIM’s ICCID (printed on the SIM card/packaging), and your account PIN
    • Don’t Miss These Guides
  • Fix the ā€œInvalid SIMā€ Error on iPhone & Android After Unlocking
  • ā€œEmergency Calls Onlyā€ After Unlocking Your Phone?
  • Pawn Shop Phones: How to Check IMEI, Blacklist Status and Carrier Lock Before Buying

    • Quick Reference: Who Fixes What

    Problem ConfirmedWho Fixes ItContact
    Phone still carrier-lockedYour old carrierAT&T: 855-223-0558 Ā· T-Mobile: 844-839-5057 Ā· Verizon: 1-800-VERIZON
    SIM not activated / port stuckYour new carrierTheir support line or app chat
    Phone incompatible with new networkYou ā€” pick a compatible carrier or phonePlan help: 855-696-0156
    Blacklisted IMEIThe carrier that flagged it (or the seller)Any carrier store can run the IMEI
    Hardware fault (SIM reader / antenna)Manufacturer or repair shopApple Support / Samsung Care, etc.

    How to Avoid This Next Time You Switch

    A five-minute pre-check before you order a new SIM prevents almost every scenario in this guide:

    • Verify unlock status on the phone itselfĀ (Settings ā†’ About), not just the carrier’s email. Especially important for Verizon devices bought after January 2026, which stay locked until paid off.
    • Run your IMEI through the new carrier’s BYOD checkerĀ before signing up ā€” it takes 60 seconds and confirms full band, VoLTE, and 5G support.
    • Get your porting info right:Ā account number and transfer PIN from the old carrier, requestedĀ beforeĀ you start the switch. A wrong PIN is the #1 cause of stuck ports.
    • Don’t cancel your old line early.Ā Let the port cancel it automatically ā€” cancelling first can void the number transfer and complicate the unlock.
    Frequently Asked Questions
    How long after unlocking should I wait before the new SIM works?

    Most unlocks apply within minutes to a few hours after the carrier confirms them, but some take up to 48 hours to fully propagate ā€” especially if the carrier processes unlocks in batches. If you’re past 48 hours and the phone still shows a SIM lock in settings, call the old carrier and ask them to re-push the unlock to your IMEI.

    Why do calls work but mobile data doesn’t on my new SIM?

    That’s the classic signature of a wrong APN. Voice can register through the network’s basic layer, but data needs the correct APN address to route through. Set the APN manually (Step 4), save it, select it, and restart. If the APN menu is missing on an iPhone, install the carrier settings update instead (Step 6).

    What does “SIM Not Provisioned” actually mean?

    It means the SIM card itself hasn’t been registered to an active line on the carrier’s system. It has nothing to do with your phone or the unlock. The fix is always on the carrier’s side: activate the line in their app, finish a stalled number port, or ask support to attach the SIM’s ICCID to your account and re-provision it.

    My phone says “No SIM restrictions” but still shows “No Service.” Why?

    Then the unlock is done and the problem is elsewhere: the new line isn’t active yet (Step 7), the APN is wrong (Step 4), the phone can’t find the network automatically (Step 5), or the phone doesn’t support enough of the new carrier’s bands (Step 9). Work through those four in that order.

    Did the 2026 FCC change affect phones that were already unlocked?

    No. The January 2026 waiver ended Verizon’s automatic 60-day unlocking going forward ā€” it mainly affects Verizon devices purchased after the change took effect in late January 2026. Phones that were already unlocked stay unlocked. But if you bought a financed Verizon phone in 2026, expect it to remain locked until the balance is paid, and plan your switch around that.

    Will resetting network settings delete my photos or apps?

    No. A network settings reset only clears Wi-Fi passwords, Bluetooth pairings, cellular preferences, APNs, and VPN configurations. Your photos, messages, apps, and accounts are untouched. It’s one of the safest “deep” fixes you can run ā€” just keep your Wi-Fi password handy for afterward.

    Can an unlocked phone still be incompatible with a carrier?

    Absolutely ā€” and it’s one of the most misunderstood parts of switching. Unlocking removes the software lock, but the phone’s radio hardware determines which frequency bands it supports. International models and carrier-specific variants often miss key bands for U.S. networks, which shows up as weak signal, no 5G, no VoLTE, or full “No Service.” Always run the IMEI through the new carrier’s BYOD checker before switching.

    Should I use a third-party unlocking service if my carrier refuses?

    Be careful. If the carrier refuses because the device isn’t paid off, is on a prepaid lock timer, or is blacklisted, third-party services can’t legitimately change that ā€” and many are scams. Legitimate carrier unlocks happen through the carrier itself once you meet its posted eligibility rules. If you believe you qualify and are being wrongly denied, escalate with the carrier and reference their published unlock policy; you can also file a consumer complaint with the FCC.

    Disclaimer

    This guide is for general information only. Menu paths, APN values, carrier policies, and unlock rules change over time and can vary by device model, region, and plan. Always confirm current details with your carrier or device manufacturer. Unloky may receive compensation when you call listed numbers or sign up for services through this page; this does not affect our editorial recommendations. Last verified: August 8, 2026.

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