You don't have permission to access /UI on this server. Additionally, a 404 Not Found error was encountered while trying to use an ErrorDocument to handle the request

My Cloud OS 3 Personal & Network Attached Storage My Cloud
1

You don’t have permission to access /UI on this server.
Additionally, a 404 Not Found error was encountered while trying to use an ErrorDocument to handle the request.

2

What are you exactly trying to do … Access the Dashboard or Transfer/Open a file? Are you doing this locally or remotely?