Severity: error --> Exception: Class ’DOMDocument’ not found /var/www/ezlogin/application/third_party/saml/src/Saml2/IdPMetadata Parser.php 113

 If you are getting the above error, you need to install the  DOM  extension. You can do so on Debian / Ubuntu using:

And on Centos / Fedora / Red Hat:

If you get conflicts between PHP 5 and PHP 5.3 packages, you could try to see if the php53-xml package exists instead.

Restart the web server after installing Dom extensions,
In Ubuntu