Home internet 5G gateway shows internet, devices connect but no internet

I set up my 5G home internet gateway yesterday and all worked well. Today I can connect devices to the gateway but there is no connection to the internet. The gateway shows very good connection and that I am online, but alas I am not online. I’ve restarted the gateway, told devices to forget the connection and then reconnected. But none of my devices can get a signal. Not sure where to go next other than to sit on hold for a few hours to get through to T-Mobile