Do you mean "Watch Here," where you can watch a program on your iPhone? If so, that function is working on my iPhone 6.
If that's the function you're having the problem with, you might try completely closing the FiOS Mobile app. If that doesn't correct the problem, uninstall the app and then reinstall it.
If that doesn't fix the problem....I dunno. Maybe another user here will come up with a suggestion that works.