It's been years since this problem was first flagged, and it's still happening. Sometimes removing the app from memory and then relaunching works. Some have recommended rebooting the router, rebooting the Fios TV box or both. Tonight I tried all of the above, and nothing worked. I can't access any of the Fios channels; they all give me the "channel unavailable for streaming" message—at home on an iPad that is less than 6 feet from the Fios router and upstairs from the Fios streaming boxes. I am among the Verizon customers who watches more TV on my iPad than I do on my actual TV, so the fact that this app has been this dysfunctional for so long is really unacceptable. We would love to hear from a Verizon representative here on why this app keeps behaving so poorly and what the app programmers intend to do about it.
Reach out to support directly on Twitter, or here:
Tell them the problem, more contact means more action. In the meantime, I suggest having billing department re-authorize your account.