Users with the username that has "@" cannot clone a repository.

For example, if you have a username in this format - 'user@group':

#1 Login works fine via SourceTree.
#2 Cloning has an error instead - it comes up as 'user@host/path', ie without the '@group' part.

The workaround is to fix the URL to this: 'user%40group@host/path'.

SourceTree should at least detect the "@" symbol, and auto-convert to "%40".