I can't setup public key authentication for one particular user on a system. I checked user home and .ssh directories permissions, and it's good (drwx------. both, the same as for other users that can auth by public key). I found somewhere in the internets an advice to stop sshd and run it with -ddd option to get some more information (sudo /usr/sbin/sshd -ddd). The weird thing that if I run it that way then it's working for the user.
Any ideas on this strange behavior?