I NEED HELPMY PHONE IS NOT CONNECTING

[Muthatee]

Just arrived in US

have the add on and phone wont connect to data roaming 

cant make calls or anything

[softech]

@Muthatee 

you got the proper roaming add-on or a Canada-US plan?

Critical part to US roaming depends on T-Mobile/AT&T coverage and whether you can connect successfully onto either network.

If the phone is not connecting to T-Mobile/AT&T, change the Network Connection from Automatic to Manual and select and test both T-Mobile and AT&T and see which one you can connect.

If your issue is with data, make sure your Roaming Mobile data is enabled and you have disabled your mobile data limiter.  Also change your network mode to 4G (and don't try 5G until you can connect and works on 4G)

If your issue is with voice, make sure VoLTE is enabled on the device setting.  And if it does not work, try to change the Network to T-Mobile ONLY, and change  Preferred Network Type or Network Mode to 2G and see if the calls go through.
Also, you can download VoIP app TextNow as a workaround to make calls and text if you have Wifi or if your roaming has data component and data  is working

[Phil_Adelphus]

@Muthatee   Do you have data roaming turned on in the phone settings?  You need to connect to either T-Mobile or AT&T, set the phone to 4G/LTE (don't use 5G).  If you still can't do voice calls try setting to 2G on T-Mobile in case your phone is not VoLTE enabled (what phone do you have?).  I'm assuming you have either a US roaming add-on or a Canada/US plan?