Verizon Fios Mobile app and digital AV adapter not working.

I have verizon fios and the verizon fios mobile app but with the digital av adapter it doesnt work. I get an error message saying,

"We're sorry Fios mobile app doesnt support video out from this device."

Any way around it? I'm using HDMI cable to the AV adapter and then HDMI to the TV. I guess i'm being cheap by not wanting to rent another set top box, but i though the Digital AV adapter would work.