Cannot Sync 1Phone 12 pro with iMac

Hello Corrie84 My problem has been resolved after a long workout with an Apple advisor. The problem was that I was using an Apple phone, iPhone 12 Pro with 5G capabilities, and my cellular provider had blocked access to that 5G service, apparently because of its expense!! Now I am anticipating that they will want me to pay more money for the 5G connection. The provider is Boost Mobile, a cheap provider that had recently been bought by T Mobile. I don't know who made that decision and why they didn't tell me this critical fact, especially as I bought the phone from them! The solution was for me thanks to my advisor who diagnosed it-kudos to her) to downgrade my phone to 4G (LTE) which I had been previously using on my iPhone 6 S for many years.

To answer your specific questions: the error message that I was getting was "no service", which meant that I could not sync my photos. I was running macOS Catalina, Version 10.15.7 (I can't upgrade to Big Sur as my desktop was bought in Late 2012 so they left me out because it was old to make the cut. I am running iOS 14.5.1 on my phone. Thank you for your interest in this matter.

BEWARE, there is a scam going around right now on a fake Apple-formatted email stating that one's Apple account has been blocked. They are asking for login information "in order to resolve the problem"!