Can't fork the repo...

I'm trying to follow the instructions for creating a new proposal. However, when I try to fork the project, my namespace is disabled (greyed out) and the tooltip reads "You've reached your project limit". I can still click it, but when I do, I get redirected to an error message that tells me my namespace is not valid. I have no idea what to do about this.

Any tips are appreciated. Thanks in advance.