What service area do you live in?
I had the same problem last month in Mpls./St. Paul metro area. They were working on the lines near me. Replacing my Cisco RNG 150N box with another one, finally got ON DEMAND back working again.
Every time I try to access the OnDemand portion of my cable service, I receive a CL17 error. I have called customer service many times; they tried their best to help but they haven't been given the ability by management to solve the problem. A customer service tech seems like a waste from reading what other customers have gone through with this problem. We receive an updated box which we installed but we are still having the problem; I don't want to keep exchanging boxes. Any suggestions on help because I am a good customer that's very frustrated.