I am unable to log into several of the Fios TV online sites. I have no problem with HBO, Max, Epix, and ESPN....but I cannot log into TNT, TBS, MTV, adult swim, CN. I have no problem logging in to My Verizon (yes I am the account holder and I have all of the billing data on my website), I click on TV Online, I choose one of the companion sites. Once on the site I try to log in, it asks who my service provider is, I choose Verizon, it attempts to access a sign-in site and then returns to asking me to log in. I spent 30 min with Verizon tech support last night and they said it's a server problem, but I don't believe them. I see that other people on these forums have had the same problem, but no one ever sent them a solution. Help!!
You might try clearing your browser cookies. I had a similar problem and it was a corrupt cookie. When the cookie for My Verizion was recreated upon a successful logon, all was well with the other services. Just a suggestion.