User automatically logged out

I have a strange situation. I was changing some settings in Portal settings to customize the page.
Later I noticed a strange behavior. Apparantly, when I visit portal page opens up good but this happens:

  1. user logo at top right disappears
  2. the user is also logged out. When I enter the url it asks for login again.

Another problem:

  1. When I login with a supplier credentials, the portal stays in login page with url
  2. Manually entering /home url after login shows a proper page.
  3. Visiting logouts user. Doesnot show any page. Just this: