I cannot login Ajenti (with correct username and password)

Hi,

I clean installed Ajenti 2.1.17 on Ubuntu 16.10 by this link. http://docs.ajenti.org/en/latest/man/install.html

I can connected on network https://IP:8000 login page is coming.
I cannot login.
User Name and password is OK, page is refreshing but cannot login.
If enter wrong UserName or Pass it giving error "Authentication Failed"
How i can fix it?

Thx