Access denied

[grandpa]

Logicaldoc 7.5 CE

Everything works fine but from time to time I get access denied when I try to login with a browser. No problem at all when I use the same credentials with a soap call.
I've managed to log in once after that, but after a session timeout everything is locked again.

Any ideas?

[car031]

you should look at the logs grandpa

The are in repository/logs