When we go to the Console view as an internal standard Salesforce user on System Administrator profile, with Skuid Permission set and licence assigned, and try to open a Case, it shows us “External Page” and doesn’t load anything, just shows a blank page.

We use Skuid in our Unlimited org and have set the “View” action for the standard Case object to a Visualforce page (accessible by profile trying to access the console Case record):
We also have Page Assignments setup in Skuid:

