Maximum execution time of 30 seconds exceeded in /home/kofccom/public_html/wp-content/plugins/wpmude

Hi when I go to create a newsletter, I get this error: Maximum execution time of 30 seconds exceeded in /home/kofccom/public_html/wp-content/plugins/wpmudev-updates/update-notifications.php on line 446"

What's going on there? I tried adding this fix, but no go: https://premium.wpmudev.org/forums/topic/fatal-error-appointments-plus

Please help!