You moved your number to a new iPhone 18 Pro, but its status bar says No Service, Searching or SOS. That does not automatically mean the eSIM has been lost. The number might still be activating, the cellular line could be off, or the carrier account might need attention. The safest response is to check what the phone actually shows before deleting a plan or starting the transfer again.
This guide focuses on troubleshooting after a transfer attempt. If you have not begun moving your number, follow our iPhone 18 Pro eSIM transfer guide first. The steps below draw on Apple's eSIM setup troubleshooting and No Service and SOS guidance. Menu wording may vary by country and language.
Understand the message before changing settings
Apple says No Service or Searching means the iPhone is not connected to a cellular network. SOS or SOS only, where available, indicates that your normal carrier network is unavailable but emergency calling may still be possible through another network. Do not use an emergency call as a routine connection test.
Check whether the problem affects mobile data, calls or messages. Note the exact alert. Keep Wi-Fi and the old phone available. A transfer generally deactivates the old SIM for that number; loss of service on the old phone does not prove the new line has fully connected.
1. Check whether your line appears and is turned on
Open Settings → Cellular (or Mobile Service in some regions). Look for the number or carrier plan you tried to move. If the line appears, open it and confirm Turn On This Line is enabled. If you use two numbers, check which line is selected for cellular data and calls. A line that exists but is turned off will not provide service.
If the line does not appear, do not repeatedly scan a QR code, delete other plans or reset the whole iPhone. Apple advises contacting your carrier to set up an eSIM when the cellular line is missing. Tell support whether you used eSIM Quick Transfer, carrier activation, a QR code or the carrier's own app. The answer determines which activation method they should check.
2. Reconnect to the network
Stay connected to a reliable Wi-Fi network or hotspot while activation completes. Apple's eSIM troubleshooting lists Wi-Fi as a normal setup requirement, with exceptions for certain eSIM-only models and regions. Then turn Airplane Mode on and off. For a No Service or SOS connection problem, Apple recommends leaving it on for at least 15 seconds before turning it off.
Check the carrier name after each step. If your line is visible, toggle it off and back on, then restart the iPhone. Work through these checks once in order so you know which step helped.
3. Check iOS and carrier settings
Apple advises using the latest supported iOS version when setting up eSIM. Connect to Wi-Fi, make a backup if you need to update, and check Settings → General → Software Update. Do not install an update from a link in a text message or an unofficial download site. For other new-phone setup checks, our iOS 27 after-update checklist covers useful settings after installation.
Next open Settings → General → About while connected to Wi-Fi. Wait briefly for a possible carrier settings update prompt; choose Update if Apple shows one. You can also see the carrier settings version beside the carrier under the eSIM section. A missing prompt does not necessarily mean something is wrong. Carrier settings cannot be fixed by downloading a random configuration profile from the web.
4. Check coverage and your carrier account
Ask your carrier whether your plan is active, the number has been moved to the new device, your area has coverage, and there is an outage or account block. Only the carrier can inspect its activation records and account details. If the new phone was bought for a different market or is tied to another provider, ask about device compatibility and any carrier lock. Apple explains that a carrier-locked iPhone can be used only with that carrier until it is officially unlocked.
If you are travelling between the United States and Europe, check whether the line's roaming arrangement covers your location. Cellular Data and Data Roaming settings can affect mobile internet abroad, but turning roaming on without checking your plan could incur charges. A separate data-only travel eSIM does not automatically move your primary phone number. Check which line handles calls, texts and data before changing it.
5. Prepare useful details for carrier support
Before calling, record the exact error, your number, the carrier's name, the transfer method and whether the plan is visible in Settings → Cellular. Apple says the carrier may ask for the iPhone's IMEI or EID, which you can find in Settings → General → About. Give account PINs or activation information only through your carrier's verified support channel. Never post a QR code, EID, account password or activation token in a public comment.
If the carrier confirms the account and network are fine but the issue remains, use the official Apple Support app or contact Apple. Apple notes that iPhones running iOS 18 or later can use the latest Apple Support app for additional diagnostics. Hardware service may be needed in some cases, but a No Service label by itself does not establish a hardware fault.
What should you avoid?
Do not erase the old phone until data, account access and working service on the new phone are confirmed. Do not remove an eSIM as a first troubleshooting step; you may need the carrier to issue a replacement. Avoid “eSIM unlock” downloads and strangers offering to activate the line for a fee. The supported routes are iPhone settings, Apple guidance and the carrier's official activation process.
Frequently asked questions
Why does my old iPhone have no signal now?
When a cellular plan transfers to the new iPhone, the old SIM for that plan is deactivated. Check the new phone and ask your carrier about activation status rather than trying to reuse an expired QR code.
Why can I use Wi-Fi but not mobile data?
Wi-Fi and cellular service are separate connections. Check that the intended line is enabled and selected for cellular data, then confirm your carrier plan is active and your location has service.
Should I reset network settings or delete the eSIM?
Start with Apple's less disruptive checks above. If the line is missing or activation still fails, contact the carrier before deleting a plan or resetting settings; it may need to reissue activation details.
Fact-check note: Reviewed Apple's support instructions on September 26, 2026. Device, carrier and country support can differ. Recheck Apple's pages and the relevant carrier's current instructions before publication.