I have solved the problem just a min ago. Within this "Multiplayer" topic, there are tons of threads about my problem. I didn't looked them before this topic i am sorry for that One of that topics, there is a solution that worked for me (i use SS 6.4). Just copy-paste this code in your "default.cfg" file.
Before doing this it is good to backup the original file of 'default.cfg'.. As i said that this will make you defend your armies, and will disable that password thing.
(this information is taken from 'benczeb90' ... Thanks to him.)
I can't change topic's title to 'SOLVED'... Can i ask moderators to change it?