Environment - Salesforce Developer Sandbox
Unable to view, access or edit User Interface settings under Setup
Current user Profile- System administrator
License - Salesforce
I have have checked my profile permissions for access to 'View setup and Config' which is checked. It does not have API only user checked either. There is no error displayed
Nothing opens when I click on User Interface or App menu under it
I can see other pages opening up such as Global action, Density settings, Action Link Templates under it and also can access it
If the permissions are already correct and other Setup pages are loading, it could be a browser/cache issue. Try clearing the browser cache, using Incognito mode or another supported browser, and then access Setup → User Interface again.
Hope This Helps!!