Netflix only ever plays one episode / movie?

Hi

I have been using Netflix on multiple devices for several months, but I have a problem on my Mac: I can only watch one episode or one movie at a time, when the next episode comes automatically or I click on something else to stream, I get one Error message. It only works again when I have completely restarted Safari. This is really annoying because I mainly look at the Mac. Does anyone have any idea what the problem could be?

How exactly is the error message?

Added a screenshot

and at autoplay there's no black screen

Check the net for your error code.