Entire website down due to site wide message error

A colleague had added a site wide message with a link in, but hadn’t closed the link, so now the entire website has an error. When I go into site-wide message to untick the show message box, because the link hasn’t closed it has made the entire page one big link to the website we put in the site wide message.

See screenshot here: https://www.flickr.com/photos/150017012@N05/shares/kb8V4Z

I am unable to untick the show message box or click submit, can anyone send me the link to what the submit button is please? What does it say when you hover over submit normally to save the changes?

Drupal version: 

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