I've now discovered that every day at 2:00am GMT while playing on the server I lose connection and the webinterface becomes unavailable. I can't say for how long that goes on as I mostly go to sleep when it happens. But has it got something to do with my server or with nitrado? I have an automatic restart configured BUT set to between 3:00am - 6:00am when the server is empty, so theres that.
Anybody has a clue?