Unable to make a call from US to UK

I tried to call a UK number, and I dialed it correctly (with "01144" before the local number, and also tried with "+44" before the local number). The smart ID feature correctly identifies the business that I'm trying to call, but a recorded voice tells me "Your call can not go through as dialed, make sure you dialed correctly."  I DID DIAL CORRECTLY. I called Tmobile support and confirmed that I was dialing correctly, and they are not able to help. (Also, the service rep said she would call me back to check on whether or not I was successful in re-trying my UK call… but she never called back.)

Does anyone have any experience with what could be causing this issue?  I don't know if there are setting in my phone that's causing it (Samsung Galaxy S22), or if there's a setting in my Tmobile account.