I think the “Don’t have an account? Create one now” link is not necessary because mattermost can create an account automatically if an user who is not member of the team tried to login by Gitlab SSO.
If the team does not allow users to signup, mattermost could tell why the user cannot login.
I think this option only appears because “Allow anyone to sign-up from login page” is set to true and signup with email is still enabled.
The message is displayed even if signup with email is disabled.
Furthermore, the page itself may not be necessary for a mattermost site whose the only way to authenticate is gitlab sso.
“Allow anyone to sign-up from login page” is true? Setting to false will make that link disappear.
Yes, I set it true because I want to allow anyone who has gitlab account join my team.