As always no replies, I figured out the problem myself.
I probably forgot to mention, that it is a vz container, so basically what had to be done:
vzquota off $cont_id
edit file /etc/vz/conf/$cont_id.conf
and changed line from :
save file, than run
vzquota on $cont_id
It will take a while for it to recalculate user quotas, after start, I recommend to delete previously created users with errors, and recreate new ones.