[Dovecot] Permission denied

Dovecot is faulting on an error about permissions that it shouldn't do.

I've got an user with its home dir with permissions 700, and inside the mail directory with the mboxes. In the error log I can see: 'Can't chdir to /home/user. Permission denied'

I wonder why it has to chdir to that directory and why it can't access. Shouldn't it be running as the user?