EP Site keep asking password and not working

Hello,

I am facing weird problem here.

I installed Sharepoint foundation 2013 and  Enterprise portal successfully.

I can run the Sharepoint central admin site, but not the enterprise portal site which got created using Enterprise portal installation.

It's keep asking password as soon as I hit http://servername

My EP site is installed on default sharepoint -80 site hence it should be accessible by http://servername

I tried to access using aos account, bcproxy account, installer account etc.

but not working at all. not sure what to do now.

any help would be much appreciated.