Apple today updated a support document with details on why iMessages might show a “Not Delivered” alert, appear as SMS/RCS messages in green bubbles, or come from your email address instead of your phone number.
As spotted by MacRumors, Apple says that these problems might stem from not activating your eSIM when you set up a new iPhone with iOS 26. When you choose to set up your eSIM later in Settings, iMessage does not activate automatically.
This means that after you set up your eSIM in the Settings app, you’ll also need to manually activate iMessage:
In the Settings app, tap Apps. Tap Messages. Turn iMessage off and back on.
This advice seems to primarily apply to people who skip the eSIM setup step during the initial setup flow of their new iPhone. It might also impact people who switch carriers and set up a new eSIM in the Settings app.
This is at least the second iMessage glitch that has impacted users since iOS 26 was released. Earlier this month, Apple shared another guide on what to do for iPhone users who are unable to activate iMessage with their phone numbers.
Have you had any problems with iMessage since updating to iOS 26 or getting a new iPhone recently? Let us know down in the comments.
My favorite iPhone accessories:
Follow Chance: Threads, Bluesky, Instagram, and Mastodon.