When using the Discourse 1-click app on DigitalOcean, and going through the initial setup over SSH, I entered my email address like I do everywhere:
Then I signed up the first account using the exact same characters:
I was surprised when, after activating the account, I had no access to the admin panel.
Starting over and entering this as my email:
worked. Perhaps email address should not be a case-sensitive comparison. See prior issue