Good morning @stephen1
All is well on the Auth0 Status front. Thank you for the latest HAR file that you included in our direct message thread as well.
This login flow involves multiple calls from the browser to Auth0. Auth0 sets a cookie in the first request which the browser would pass back in the subsequent requests. If the subsequent requests did not contain the cookie, the error would be thrown.
One possible reason for the browser to drop the cookie is because the user’s device time is off by a large margin. The cookie has an expiry similar to the session timeout configured in the Auth0 tenant, and if the time is off by more than that timeout, the browser may drop the cookie. Can you first check to confirm the time and timezone settings are correct?
Thanks in advance!