Recently, we have moved from an old forum to discourse based forum.
The usernames on that forum were allowed to have double underscores (or multiple special characters) in the usernames.
Seems like discourse doesn’t allow those usernames. Due to this, some users are not able to login into discourse from our website using Single Sign On.
They are getting a login error.
What can be the possible solutions to this?
What exactly are the rules when creating a new username on Discourse? I am not able to find them anywhere.