Phone Does not work in US.

[Debwell]

My phone does not work in US even after I purchased proper add on

[softech]

@Debwell 

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

[dust2dust]

Did you buy the roaming add-on or the US minutes add-on? Do you know if your phone has been enabled for volte here yet? Set the networks to 4G LTE and then data and text should work fine on either network. If you phone is not enabled then your only option is T-Mobile using their old 2G GSM network. Some phones and areas might do the switch down themselves or you might have to manually switch down.

[Handy1]

@Debwell  Reboot the phone and make sure your connected to T mobile or AT&T also ensure you have data roaming turned on in phone setting also 

[hairbag1]

@Debwell 

for data, make sure Roaming Data is enabled in the settings. For talk, make sure you're using T-Mobile or AT&T as prefered network. It would be handy to know if your phone has volte enabled.