I have this same problem. I have researched it a bit and read that some stations have recently implemented a type of recording protection which will allow you to record and watch tv but you can’t watch it on other pcs. I have also read that this new technology is buggy and unreliable. In my case, I was trying to watch the show on the same pc it was recorded on, and I had not done any new changes to my pc or anything weird. I search a long time to figure it out and finally gave up without an answer. The only thing I could suggest will not help you recover existing recordings but may help you in future. Get the latest updates and patches from Microsoft and then reset your DRM (digital rights media). I have included reference links below.