Drupal kept redirecting to port 80 after user logs in

I have implemented simplesamlphp on our site. After the user has been authenticated from Shibboleth and returns back to Drupal, it redirect to mysite.mainsite.com:80 and the page said, “This page can’t be displayed”. I don’t think it’s simpelsamlphp_auth because it is working fine authenticating. Any suggestion in troubleshooting this thing is much appreciated.

Drupal version: 

Source: https://www.drupal.org/taxonomy/term/22/feed