Check your bill to make sure you are being billed for Quantum.
I had the service, but was being billed for DVR service.
After that, try it first from home while on the FIOS network.
If that doesn't work, try rebooting your rotuer and DVR.
After that, use the help feature to create a ticket for them to investigate.
Its helpful to go ahead and attach the log to your ticket.
This is what I posted to another topic with this issue:
A couple of things I did to get it to work. First, if you had previously installed the FIOS app, you need to completely uninstall then re-install it. Doing an Update (manual or automatic) did not actually allow it to play - probably something in the data stored by older versions of the App.
Once you install the latest, you need to access your DVR from your home network, this will identify your mobile device to the Media Server. Once you do that, you should see a Green Checkmark above the icon representing the Media Server on the "DVR" page of the app (it's on the upper right of the screen, on the ribbon where the "Sort by" choices are made.
You can verify that the Media Server sees your mobile device by looking at the main menu "Settings -> System -> Mobile Devices - Active Device" where it should list the device (using the somewhat generic names like "Galaxy Tab A" for my tablet).