T-mobile has awesome phone plans for people living in America to get free international roaming in over 140 countries. For most people, all they’d have to do is flip the switch on their phones that enable international roaming. For a minority of people, there are a few more settings to mess with. In the past year, I’ve had two issues that resulted in me losing my data connection outside of USA and I’m documenting some things below to try since it worked for me – maybe it’ll help some people out.
Check that international data roaming is enabled
Toggle data roaming on the carrier side
Dialing #763# will turn off the roaming on the carrier side (as opposed to just the phone), and dialing #766# will turn it back on. Restart the phone.