Yesterday, Zwift experienced a confirmed outage (1/7) and I was riding at the time. When I saw everyone disappear, I didn’t know if there was a problem with my internet connection or with Zwift but as something to try, I restarted the mobile phone client (I have an android) and was given the error message “user ID or password is invalid”. I definitely know my password and as soon as I started seeing other riders on the course, I was able to connect on my mobile phone.
I would propose that Zwift improve error logging to differentiate connections problems from failed authentication requests. It creates confusion when the error says that you have a bad ID or password but in reality, the client doesn’t seem to be authenticating you.