[otrs] Problem after removing

Dear all, I was going to test OTRS on a server where I had another webapp, that was working fine. After testing OTRS, I removed its package through apt / aptitude. The problem I face now is that the other webapp is unreachable, throwing a 500 error. Other files/folders (static) on the server are OK, but cannot connect to that web application. Any idea what could OTRS have changed on Apache to restrict/block access in some way? Thanks. Rodrigo