[skido]

Yes, I have tried to search matching cases with Google but without success. And as I already mentioned, also contacted store technical support but no solution from there either.

Since the problem is really tricky I felt I need some expert level help. On the other hand I should maybe accept that the problem is remotely unsolvable. I was hoping that error message produced by Fiddler (userinvalid.mp3) would raise association in someone's head but it looks like it does not help.