Lock onto network while roaming

[Android Central Question]

I am using a Huawei p20 while roaming in the US and for some reason my phone wants to roam on T mobile while I want to be on AT&T where the data speed is much better. But when I disable the automatic network select and manually select AT&T it will only stay on the network for a short time while the signal is great. But as soon as I select the network the setting will automatically go back to auto select network anyway to permanently disabled the auto select network?

 

[VidJunky]

Does your carrier have an agreement with AT&T? Your SIM may be keeping you off of networks where your carrier doesn't have an agreement or risking charges may apply.

Are you sure you're in an AT&T area? Most devices will attempt to get you on the best network with the strongest signal, regardless of speed, and in the area you're in that might not be AT&T.

While roaming is mostly a thing of the past some companies still require agreements or additional plans, say if you're traveling outside of your home country, and often the roaming notification is just that, a notification that you are not on your home carriers network. Gone mostly are the days of being charged extra or separately for use of a network not branded by your carrier and honestly that's probably where you need to turn for assistance with this, your carrier. They will know which networks are available to you, they will have coverage maps and device compatibility on those networks.