I had time this morning to make some tests, and then i chatted with tech support of NowTV. I found a guy who's very kind...he suggested me to do, when playing something on web player, to pause the stream, then close the player, then exit the content (and so return to the home page, waiting a miunte or two, because the server side of that streaming can have the time to stop itself.
That error message could not occur.
If the situation will prompt again, wait aa few hours to check the issue is gone.
Weird, but it works. Just exercise patience.
