Causing Error Editing Pages?

Every time I attempt to edit one of my pages I get the following error. [Edit]Also, occurs when viewing forms and submissions.

View post on imgur.com

Forms are still working, but unfortunately I cannot close the dialog box and therefore cannot edit any pages at the moment.

Note: This is happening even on pages that aren’t utilizing the forms shortcode.

Quick fix? Aside from deactivating the plugin?

https://wordpress.org/plugins/custom-contact-forms/