Symptoms

Getting an error after adding Appit to production site
 

Diagnoses

After adding the K2 Appit app to our production site, I tried clicking on the Appit icon to go into the administration settings page and instead I get an error that seems to have something to do with branding. Attaching a screenshot here.
 

Resolution

We were able to identify the problem, which was that the company that did the site branding created a solution that pushed the master pages directly to all new sites when they were added. This caused an issue with the app not being surfaced on the site which made it impossible for the customer to Appify any lists or libraries. It was found that disabling and deactivating the solution fixed the problem.