After installing iOS 26, some users have noticed that iMessage stops working normally. The most common issues include messages not arriving, conversations switching to SMS/RCS, and difficulties using the linked phone number to the iPhone.
Apple has acknowledged the problem and has published an official guide with the recommended solutionThe root cause lies in a specific configuration of the moving line, and fortunately, the fix is relatively simple if you follow the steps provided.
What's happening with iMessage after updating to iOS 26?
Según un Apple support document, the error appears on devices that have an active SIM and an inactive one associated with the same number, either as a physical card or as a eSIMThis duplication can prevent iMessage from activating properly and disrupt the sending and receiving of messages.
Symptoms that reveal the failure
Before applying changes, it's a good idea to confirm that you're experiencing this specific issue. Apple details several clear signs that point to the error after updating to iOS 26:
- “Not delivered” message when trying to send iMessages.
- Messages that pass to SMS/RCS and are displayed with a green bubble instead of a blue one.
- Shipping from a mail address instead of your phone number.
- The same number appears duplicated in Settings > Apps > Messages > Send and receive.
The cause: an inactive SIM with the same number
The coexistence of an active and an inactive line with the same number confuses the system. In practice, iMessage doesn't know which line to activate and can choose to send from email or downgrade to SMS/RCS. Identifying and removing that inactive SIM card is usually restore operation habitual.
Official solution: Remove the inactive SIM and reactivate iMessage
Apple indicates that the most effective measure is withdraw the line that's not in use. If it's a physical card, remove it from the tray; if it's an eSIM, delete it from Settings. Then, reactivate the number in iMessage to get it working normally again.
detailed steps
- Open Settings and go to Mobile data (or Cellular).
- If two lines with the same number appear, locate the one that is inactive.
- If it's a physical SIM, remove it from the iPhone.
- If it is an eSIM, press remove eSIM to delete it.
- Go back to Settings and access Apps.
- Sign in Messages.
- Toca Send and receive.
- Select your phone number to activate iMessage.
Once this is done, the service should send again with blue bubble and correctly associate your number with iMessage, preventing messages from being sent as SMS or from email.
If it still doesn't work, try this.
If the activation of iMessage or FaceTime doesn't work the first time, Apple suggests a few additional attempts that may resolve the issue.
- Turn off iMessage and FaceTime, restart your iPhone, and turn them back on.
- Check your iMessage/FaceTime account activation online, if applicable.
- Sign in using a mail address in Messages or FaceTime temporarily.
If the error persists after these measures, check again that there is no inactive SIM associated with the same number and repeat the activation process in Settings > Messages > Send & Receive.
The issue stems from a specific configuration of the mobile line after the iOS 26 update: a duplicate inactive SIM. Identifying and removing it, then reactivating iMessage with your number, is the most direct route to get back to your regular Messages experience without losing messages or seeing the dreaded “Not Delivered” message.
