Trust me, you won‘t find it. I am onto this problem for 6 months now. The fact that even now I am unable to recreate it on purpose says it all. It is mostly random and the message never makes sense anyway.
Then I spent my time finding a way to disable that message. No luck either. I just want the message gone but there simply is no option for that, even in advanced settings.
Asking for help is frustrating too because people believe you have a problem with the speed of your connection or hard drive. People don‘t read what you write, even Sam didn‘t really. IT IS NOT A SPEED PROBLEM. But even if people read that, they have no answer because this message is usuall associated with buffering problems on internet streams (usually illegal ones), not with local streaming.
So in the end, there is not much you can do besides making one change at a time and then play content for some days or weeks to find a pattern or not.
I actually gave up some weeks ago…l until I read your post and it got me started again,