So, you're having trouble getting iMessage to play nice with your phone number after updating to iOS 26? You're not alone. It seems some iPhone users are running into a snag where iMessage just won't activate properly, especially if they've got a dormant SIM or eSIM hanging around with the same digits as their active one.

When this happens, it's like your iPhone gets a bit confused. You might see those dreaded "Not Delivered" alerts when trying to send iMessages. Even worse, you might find your messages are being sent as regular SMS or RCS texts – those green bubbles instead of the sleek blue ones we all know and love. In some cases, your iPhone might even resort to sending iMessages from your email address, which isn't ideal.

The Fix? It's Simpler Than You Think

If you're experiencing this issue, Apple suggests a pretty straightforward solution: remove the inactive SIM. Seriously, that's it. If the inactive SIM is a physical one, pop it out. If it's an eSIM, you can delete it through the Cellular settings.

To actually remove the eSIM, hop into Settings, then Cellular. If you see two SIMs listed with the same number, delete the one that's not in use. This is important because I know that sometimes we can forget that we have an old eSIM.

Once that's done, you should be able to reactivate iMessage by heading to Messages, tapping on Send & Receive, and selecting your phone number. Hopefully, that gets everything back on track.

I know, it can be annoying when things don't work as expected, but at least there's a relatively easy fix for this particular iMessage hiccup. Just a little housekeeping, and you should be back to sending blue-bubbled messages in no time!