This is an ongoing problem for me. When I try to send Messages to non-iPhone people about 75% of the time I get the “Not Delivered” error messages.
I have SMS and MMS both turned on in settings|messages
I am using iOS 12 on an Xs. THis problem also happened on my X with iOS11
I experienced a similar problem yesterday after migrating to a new phone.
Let me guess… are you a Verizon Wireless customer?
I had to call them a couple times to get my phone to activate; eventually I had to read the IEMI and ICCID numbers to them and after a LONG time, it seemed to activate. Everything seems fine except for texting non-Apple devices.
I thought there might be a “carrier update” soon.
I had an issue like this and there were two possible causes:
- One of my recipients was on Verizon and having activation issues.
- I had a cannot send message on my laptop.
When I cleared #2 everything started working fine again. I’m on T Mobile using an XS Max.