Reload failed because retrieve_conf encountered an error: 255

FreePBX 13.0.15
Asterisk 11.14.2
SHMZ release 6.5 (Final)

With this specific server, my trend has always been to grab all available module updates, and have succeed with no errors. However, now, I’m receiving the error below. What could be causing this problem?

Reload failed because retrieve_conf encountered an error: 255

exit: 255
PHP Fatal error: Class ‘DomDocument’ not found in
/var/www/html/admin/libraries/Composer/vendor/fguillot/picofeed/lib/PicoFeed/Parser/
XmlParser.php on line 143
Whoops\Exception\ErrorException: Class ‘DomDocument’ not found in file
/var/www/html/admin/libraries/Composer/vendor/fguillot/picofeed/lib/PicoFeed/Parser/
XmlParser.php on line 143
Stack trace:

  1. ()
    /var/www/html/admin/libraries/Composer/vendor/fguillot/picofeed/lib/PicoFeed/Parser/
    XmlParser.php:143

Run
yum install php-xml

After running this command, the error can no longer be produced. tm, thanks!