error/moodle/usernamelowercase
From MoodleDocs
The url for the moodle site attempting to register with a hub can not contain upper case letters. So a site like http:// somemoodle.org/2000_Spring will return an error and point to this page you are reading now. Even though it is perfectly valid to either upper or lower case letters in the folder portion of a url, it won't work in this case.
