Ajax Stand-alone chat "Invalid Username"

[deepndark]

Hi!

I have installed Ajax Standalone chat for my site. I have added 2 registered users to the database.
At the beginning I successfully was able to log in. But not anymore - it says "Invalid Username"
I'm still able to log in as admin tho.
Why is my 1st username "deepndark" not able to get logged anymore.

Things I did was adding another user to the chat's database. Otherwise i didn't do anything.
Please help!

[live627]

I'm gonna  move this to the support boards. But first,  to help me decide, what is your smf version?