Roundcube has blank login screen after upgrading to PHP7

[Morons]

My Error seem to be!

[17-Jun-2020 14:33:39 UTC] PHP Fatal error:  Uncaught Error: Class 'DOMDocument' not found in /usr/share/roundcube/program/lib/Roundcube/html.php:357
Stack trace:
#0 /usr/share/roundcube/program/include/rcmail_output_html.php(905): html::parse_attrib_string('condition="conf...')
#1 /usr/share/roundcube/program/include/rcmail_output_html.php(633): rcmail_output_html->parse_conditions('<roundcube:obje...')
#2 /usr/share/roundcube/program/include/rcmail_output_html.php(488): rcmail_output_html->parse('login', false)
#3 /usr/share/roundcube/index.php(248): rcmail_output_html->send('login')
#4 {main}
  thrown in /usr/share/roundcube/program/lib/Roundcube/html.php on line 357
root@ares:/var/log/roundcube# php --version
PHP 7.2.24-0ubuntu0.18.04.6 (cli) (built: May 26 2020 13:09:11) ( NTS )

I installed the server with bolow guide (16.04 version) and it worked perfect BUT when I did a Dist Upgrade to 18.04 and PHP7 was loaded I started to get issues wherby the login page for Roundcube is just blank!
I also had issues with phpmyadmin but a simple update fixed it!

https://www.howtoforge.com/tutorial/perfect-server-ubuntu-18.04-with-apache-php-myqsl-pureftpd-bind-postfix-doveot-and-ispconfig/3/

[alec]

You need php-dom package.