I live in SW Washington state in an area where I rely on roaming and a connection to a cellular service area provisioned by US Cellular.
I am upgrading from an iPhone 8 Plus.
This phone worked well both on Verizon LTE network while traveling and roaming (voice) only no data) when back in my home area here in zip code area 98649.
When in my house due to poor signal strength I had to rely on WI-FI calling and all was fine.
When out and about I could least make voice calls if needed via US Cellular’s network.
This has been true with all of the iPhones I have owned while living here. iPhone 4, iPhone 5s, iPhone 6sPlus, and my iPhone 8 Plus prior to the purchase my iPhone 12 Pro Max.
Well after getting this new iPhone sold directly form Apple to me (With no Sim provided)
I setup the new iPhone here at home via WiFi as a new device and did not move anything over on to it.
I setup all my apps & allowed all my information / Contacts , Notes & Calendar, etc. to populated to the phone via WiFi prior to activating it on cellular service.
I took a gamble and used my old SIM card from the iPhone 8 Plus (shame on me)
I drove 10 miles into CastleRock Wa. so I would have LTE coverage and put my sim in and activated my phone.
All seemed well phone fired up got LTE and I tested by calling my voice mail.
I immediately received a text message from Verizon saying:
Verizon Msg: We noticed you switched the SIM card in your 5G device. To get access to the full benefits of 5G, please use the pre-installed 5G SIM card that came with your device. If you're unable to locate the original 5G SIM card or did not receive one, visit verizon.com/support/contact-us to contact us for help in completing your activation.
Well I headed back to my home and went from good LTE to no signal……by the time I got to my home.
So Monday November 23 I drove down to Vancouver Wa. (40 Mile drive oneway) to the Verizon store and installed the new sim.
While leaving there I had great 5G service and along the way back home up the I5 freeway LTE was also very good .
As I got off the main freeway and headed towards my home as I got to the area where I normally switch from LTE to Extended ( Roaming) I get no bars...and the phone will no longer function on a cell network.
Once home wi-if calling kicks in and all is good again.
As long as I stay in the house or in my shop.
I contacted Verizon 4 times on the 23rd and with the (help?) from the tech’s we went over all settings.
Reseting network settings, airplane mode on and off, cell on and you name we tried it.
We made sure there were no carrier updates that were listed and needed installed
And I also made sure I was on the most current IOS available 14.2.1.
I like a lot of you are at my wits end on this.
I just wanted to share this information with you and to see if any one has happened upon a resolution.