So, I wasn’t able to take a picture at the time this happened on my phone, nor was I able to record anything going on in my phone. The phone is a Samsung Galaxy S9, and is registered on Public Mobile (Telus). To be honest, I never was required to enter the IMEI on this phone into the carrier settings on Public Mobile’s website.
And I know, your probably here only to report the same issue on a different phone, and a different carrier, in a different country. I just wanted to share what I did to my phone so I could help other people going through the same thing, and my fix may not even help you. But here goes nothing.
The fix that worked for me was by first checking to see if my billing was all up to date for my phone plan, and all was good at the time of this error happening to me. So, I knew after that, that it was just a bug that needed to be cleared out by using this one trick. The trick is to simply restart your smartphone and see what it says when you start it up again (after it shuts down). With iPhone’s of course you have to shut it down and then boot back up again. Android phones are different. Anyways, upon restarting my Galaxy S9 the phone recognized the carrier again and everything was all good. End of story. Hope this helped you.