Hmmm, it's possible that there's an issue with the HDCP protocols between the three units. The Uverse manual doesn't say anything about it having it, and the Denon manual says that connected components must have it. However, let's try to detail this out and see if we can fix it.
Btw, if you are using RedMere HDMI cables, make sure that you have them connected in the proper direction - those are directional cables.
1. Turn off all equipment
2. Connect an HDMI cable from the Uverse HDMI output to an input on the Denon (let's go with "CBL/SAT" for this example).
3. Connect an HDMI cable from the Denon "HDMI OUT - MONITOR1" port to an HDMI input on your TV.
4. Turn on Denon, TV, and Uverse receiver.
5. Select the proper HDMI input on your TV.
6. Go into the menu on the Denon.
7. If you can see the Denon's onscreen display on your TV, then you know that the Denon and TV are connected properly.
8. Make sure that the HDMI input that you're using for the Uverse receiver on the Denon (e.g. "CBL/SAT") is assigned to the proper input selector (page 115 of the manual).
9. Set the Input Mode on the Denon for that HDMI connector to "HDMI" (page 117 of the manual)
10. If that doesn't work, go into HDMI setup in the Denon menu (page 110) and set "HDMI Control" to Off and "Power Off Control" to Off.
Please let us know if anything works when you try that.