Issue connecting over WiFi

Using the latest Android app on a Pixel 4a. All works beautifully over my data connection, but Zwift refuses to log in when the phone is connected to my WiFi. Have used the same WiFi connection with a PC version of Zwift until recently with no connectivity problems. No other issues with the phone, only Zwift. I can still use the app successfully over 4G but this is a problem because to cast my screen to a TV so I can see what’s going on, I need to be on the WiFi network.

Is this a known issue and is there a fix?
Thanks

Not a known issue that I’m aware of.

Are you running any security on your phone or router?

Not running anything out of the ordinary that I’m aware of. Successfully used the same WiFi connection with a PC, Zwift just doesn’t like to connect on my phone. I guess the issue is with the phone or the way it connects to the WiFi, maybe it needs to go through a different WiFi channel or something? The error message varies between ‘can’t connect to Zwift servers’ or more often it says ‘there was a problem logging in using that account.’