SSO Broken - The requested URL or resource could not be found

Have you tried this to login:

from Setup DiscourseConnect - Official Single-Sign-On for Discourse (sso)

Essetinaly what is saying above, is that when you can’t login as admin while SSO is on you have two option:

  • go to yourforum.com//u/admin-login type your admin and try to login (this assume your SMTP server/service) is running.
  • Second option would be use ruby console as exaplined above.