Email problem

I've had the TMobile 5G gateway for a few months and it's been great. But now for some reason, I have to keep rebooting the gateway or I cannot log into my ATT email account. Everything else works fine. I can go to any website, log into other accounts, but my ATT email doesn't even go to the login screen. I just get an "Something went wrong, try again" screen. Any ideas? Thanks.