Envold Avia editor won't load

Our content editor was adding a new page that resulted in the Avia editor breaking completely on all pages. The home page slider banner is also broken.

First problems with the editor showed up when copy/pasting a bulleted list from email into the editor, but she got it to work by logging out and back in.
She made some more minor changes that all worked fine.
Then she added a banner to the page (page is called “Mitigation” and it is currently in the trash) which caused the editor to freeze up.
She was unable to find a solution, so she updated wordpress.
After the WP update, the Avia editor was broken on all pages, and the home page slider ceased to function properly.

Not wanting to break things further, the only action I have taken so far is to delete the mitigation page.

Please help.