- Plesk for Windows
- Error Document (for example, 404 Error) was changed to Default under Plesk > Domain > example.com > Virtual Directories > Error Documents > 404 Error
- After changing from Default to file, in IIS under Sites > example.com > Error Pages the path for the custom 404 error is mixed with the path of default error:
This is Plesk bug with ID PPM-8514, which will be fixed in future Plesk updates.
Currently, there is no workaround.