After installing the new version of the system, some users have detected that iMessage stops working normally on iOS 26: Messages not going out, conversations switching to SMS/RCS, and the iPhone number not being activated.
Apple has published a support notice in which confirms the cause of the failure and proposes a solutionThe cause lies in the mobile line's configuration: when an active and inactive line coexist with the same number (SIM or eSIM), iMessage doesn't activate correctly.
Why does iMessage fail after updating?
According to the company's explanation, the problem occurs if the iPhone has associated two cards (one active and one inactive) with the same numberThis duplication confuses the activation process and can block the number from being used in iMessage, forcing the system to send it by SMS/RCS or use an email address.
How to identify if it affects you
Before touching anything, it's a good idea to confirm the diagnosis. Apple details several clues that fit with this ruling After updating to iOS 26:
- “Not delivered” notice when sending iMessages.
- Conversations that go on to SMS/RCS (green bubble) instead of blue.
- Messages come out from a mail address and not from your number.
- The same number appears duplicated in Settings > Apps > Messages > Send & Receive.
Official solution: remove the inactive SIM and reactivate the number
The most effective measure proposed by Apple is to remove the unused line. In practice, this involves erase the duplicate eSIM or remove the inactive physical SIM and then reactivate the number in iMessage.
- Open Settings and go to Mobile data (or Cellular).
- If you see two lines with the same number, locate the one that is inactive.
- If it's a physical SIM, remove it from the tray.
- If it's an eSIM, tap remove eSIM to delete it.
- Go back to Settings and access Apps.
- Sign in Messages and touches Send and receive.
- Select your phone number to activate iMessage.
Once these steps are completed, the conversations should be displayed again with blue bubble and the iPhone will use your number without resorting to email or downgrading to SMS/RCS.
If it doesn't activate the first time, try this
In some cases, activation may take a while or may not be successful immediately. Apple suggests several additional actions to unblock the situation:
- Turn off iMessage and FaceTime, restart your iPhone, and turn them back on.
- Check your iMessage/FaceTime account activation online, if applicable.
- Sign in with a mail address temporarily in Messages or FaceTime.
If problems persist, check again that no SIM left inactive with the same number associated with the device and repeat the activation from Settings > Messages > Send and receive.
Is it an iOS bug or a configuration issue?
Apple points out that this is not a failure of the system itself, but rather a consequence of having duplicate lines (active and inactive) with the same number. The impact is limited to a small group of users, and the fix is simple: remove the inactive line and reactivate iMessage with the primary number.
If iMessage doesn't work after updating to iOS 26The most effective way to do this is to check for a duplicate inactive SIM or eSIM, remove it, and reactivate the service from Send/Receive. In most cases, this setting restores normal behavior without having to wait for new updates.
