Maybe you used up the data already ? Login to My Account or on the app and check what it says about the US roaming
if you still have the US roaming, could be just a network connection. Try connect to T-Mobile and AT&T manually. Could be one of the networks not working well
if you need, ask PM to check, Just open ticket with them using the Orange Chatbot icon on lower right, start typing Submit ticket, choose Contact Us and then follow the screen to login and submit ticket
