Problem with HDCP monitor

Ok so little backstory. I bought a higher end computer and monitor to use in the bedroom for a home theater PC, as well as a HDTV to use with my TW digital cable box. Been using it for a while and randomly started having problems with my cable box saying that i don’t have an HDCP compliant TV, which I do, the entire reason I bought this monitor.

So now, I can’t get it to display at all, keep getting the error message. I have an older set top box from TW in the bedroom, one of the first explorer’s that were HD/DVR’s, I don’t remember the model number, I think it is 8100.

Any idea what the issue is? I doubt TW’s tech support is going to help at all here because they will likely just tell me I need a new TV.

try another box. it might be bad as the tv seems to be working otherwise correct?

I think it is working… I need to pull it and attach it to my other box to test, it just sucks reconfiguring it initially because it won’t display w/default settings. It works perfectly fine with the PC though