admincp keep ask login repeatedly (have video)

[pjk]

Finally, I finish Vbulletin installed.

but I can't get in admincp directly, it keep ask me to login as show in video.

I have to go to forum login and then come back to admincp.

Any idea to solve it? Thank you.

[Mark.B]

Make sure your cookie prefix (not path) are identical in both config.php files. They must be identical.

[pjk]

It's work. Thank you.

PS: Just realize that I'm post this topic in wrong section. Sorry.