If you get error messages like this
Oct 18 15:38:47 server authdaemond: userdb: opened /etc/authlib/userdb.dat Oct 18 15:38:47 server authdaemond: userdb: looking up 'user' Oct 18 15:38:47 server authdaemond: userdb: entry not found
You should check that your user entry is really seperated from the the rest of the line with a tab – and not with spaces.