can not login to webmin( virtualmin)

Today I just installed VM 6 in a fresh virtual server ( Ubuntu 16.04 ) . Installation goes well without any errors. But i can not login to webmin interface. Neither root or sudo password working to login to webmin.

FYI i can login using to ssh using those credentials . So extra firewall installed . ( though firewalld was installed by virtualmin installer )

Thanks
RON

I mistake. Please mark this post as solved.

I had wrong hostname configured that caused the issue

Regards
RON