I have traditional cable (coax/CATV), and I'm using their (rudimentary) cloud DVR service on my Samsung box. So I think we've established that I should be using the Optimum app (rather than Optimum.TV app). I've tried both of those apps and I get the same error (posted above)
My experience calling support was beyond pathetic so I'm considering reaching out to the ItsOptimum folks on Reddit, but my brand new Reddit account is not allowing me to chat with them (yet?). I guess I could do a public post but I'd probably rather keep it private so I don't need to worry what info I'm disclosing.
Ah, technology... always such PITA
p.s. I do have Internet from Optimum also, but it's on a separate account so that might turn out to be a problem for the app to work right??