by Noah A.
Thank you all for your help! The first thing I tried was to change the value in the SQLdatabase, as you suggested. That didn't work. (It didn't even change the value shown in the webinterface, as I confirmed after it was in a usable state). What did work is this answer: http://stackoverflow.com/a/17107232 (configuring nginx to allow for slasharguments). Thanks for pointing me in the right direction!
BTW, I got locked out of my account somehow, that's why I have a different username.