This error message surfaced this morning. Login has been without issues everyday for last couple months. No updates that I am aware of, either Windows 10 or others. Zwift user forum has a few others reporting same issue. The only known work-around is to create a new Windows 10 user account which must be a hint.
I am confident someone here on EE will either have a good idea what is causing the error or suggest troubleshooting suggestions. zwift-login-error.PNG