mediabrowser log?

Hi, when I try to log on mediabrowser with my phone (from the web) I obtain password error. If I try in my lan, everything work fine! But If I try with a pc from the web the password is OK! So I don't think it's my setup the problem. Where is the authentification log for mediabrowser?? derby.log is almost empty, and serviio.log doesn't contain anything related to this...