Why do I get the message on my TV screen, "The DVR system is working. Please try again." when I press any button on my AT&T Uverse Remote?

The IPH8005 is the DVR.  You have one DVR.  The other boxes get the info from the DVR.  Think of it as Slave and Master.  The DVR is the Master and any other boxes are slaves.  The slaves get their orders from the master and if the master is not working, then the slaves don't know what to do.

Try rebooting the DVR (8005) first.  Then try rebooting the receiver in question.   If that doesn't work, do the following:

Unplug the DVR and both receivers

Unplug your modem

Wait 30 secs.

Plug in modem FIRST.  Allow all lights to come on

Plug in DVR NEXT.  Allow it to come and fully working

Plug in each STB separately.  Let each one start working before moving on the next one.

This is called a Whole House Reboot and many times will fix your problems.  If the problem persists, it's time to call CS.  1-800-288-2020

Did you reboot the DVR specifically?

If this is the VIP2500 box with the TV I am having the issue with, Yes.

VIP2500 is a receiver.  You should have one box with a different model number.  I have a VIP2262 and VIP2250 is another model.  Yours could be something else.

The DVR will be the box hardwired to your modem....unless all of your boxes are hardwired to the modem.

Full disclosure here - When it comes to electronics you should probably "think of me as your Grandmother".

That being said, the only box behind this TV is the one I mentioned previously. My modem is located in a separate area of the house with only a power cord and ethernet cable connected.

The other TVs have: Main TV, IPH8005;  3rd TV,  ISB7005 Cisco.

Should I restart the box behind the Main TV?

Thank you!

Thank you so much!

Followed your instructions and my problem is solved!!!

People helping people...kindness...everyone benefits, so appreciated.

When in doubt, REBOOT!