I've installed PiranhaCMS on an existing ASP.NET MVC5 application. Part from I had to install AutoMapper, the installation went through smouthly. I followed the Get Started instruction in the "Adding Piranha CMS to an existing application". I've tried using existing database, the incluede CE database, and event with a new database. It all comes down to the same problem, I get routed to "/manager/install" where I set up the admin user (which gets added to the sysuser table). After this I get routed to the "/manager" page where I get to sign in with the user i just created. When logging in, I get back to the same page. I assume, the user is not valid... but I get no exception or other information.
Any ideas?