US Roaming NOT connecting in Alaska

[jasontw]

My plan includes US Roaming. It is not connecting in Alaska on Android (OnePlus 9 Pro 5G) but same SIM card works on iPhone 12 Pro Max.
I have tried all steps that Public Mobile FAQ suggested on roaming setup in the US!

Anyone can help?

[jasontw]

The same OnePlus works fine on the trip to Rome New Yark USA. I have no problem connecting to AT&T or T-Mobile 5G network.

[Phil_Adelphus]

@jasontw   The only coverage in Alaska is AT&T as far as I know, there is no T-Mobile.  So you would have to connect to AT&T on 4G/LTE.  Yes data and text should work regardless, only voice calls should be affected with a non-VoLTE phone.

[jasontw]

@Phil_Adelphus

Phone is not connecting to the provider at all in Alaska both AT&T and T-Mobile. The error massage on the phone is something like 'Not connected'. I would assume only making or receiving a voice call that will requires VoLte and it should not impact connecting to the network for Data or Text. Please correct me If I was wrong.

I am hoping that this happens only in Alaska. I have a planned trip to US again soon. I will bring a white-listed android phone with me to try. 

[Phil_Adelphus]

@jasontw   Is anything working?  For AT&T you need to be on 4G/LTE and not 5G.  OnePlus will likely not have VoLTE with PM roaming (it's not on the PM VoLTE whitelist), which is required in the USA but that should only affect voice calls while text and data should still work.

[jasontw]

When I insert my SIM to the iPhone, it was connected successfully to AT&T automatically. ‘Auto select network’ on the Android phones (I have 2 android phones with me), none connect. I also tried manually connect to all available networks, none connect.  These are some for the things that I tried but still not connect…

1. Set Data Roaming on or off
2. Set Mobile Data on or off
3. Set Preferred network type to LTE or 5G
4. Reset APN
5. Manually add AT&T APN

[DDM69]

My iPhone worked in Alaska in July. Are you connecting to T Mobile or AT&T?  Data roaming turned on?