U-verse signal lost but changing channel works - for one minute then freezes

If you put a switch or router between the gateway and the set-top box, this effect can happen.  Because that hardware is unable to handle multicast traffic required by the more sophisticated Uverse service.   

Are you sure it's a whole minute?  As gr8sho says, when you first tune a channel, the channel is immediately sent via unicast (i.e. to your Receiver's specific address).  The Unicast stream lasts about 20 seconds.  This is intended to cover the period of time necessary for the Receiver's request via IGMPv3 for a multicast stream of the channel.  Once the receiver sees the multicast stream, it seamlessly switches to it.

If anything between the receiver and the Gateway blocks the multicast stream from coming in, or the IGMPv3 conversation from happening to initiate the stream, then about 20 seconds after you tune the channel... oops.

Thanks for the specifics.  Way over my pay grade, but that gives me a clue into what to ask the support techs, I guess.  I didn’t Time the longevity of the signal but I will.  It very likely could be 20 seconds. 

Ironically, a couple of days after an AT&T tech came out last week, worked on the lines at the street level then came inside to test them, or main TV made a popping sound and went dead. It is completely dead.  Then the second TV started this nonsense.  Maybe there’sa message here? LOL

The kind of thing that causes what we're describing is normally, as gr8sho said, a piece of network equipment between the Gateway and the TV Receiver that is blocking part of the network traffic.  Like if you decided you wanted a third party router for your networking and plugged the TV Receivers into that Router instead of directly into the Gateway... that sort of thing.

Hi, @Mp111.

Please let us know more about your setup so we determine the best course of action for you.

Aminah, AT&T Community Specialist

Try unplugging your dvr for about 30 seconds. Then plug it back in. If that doesn’t work, unplug the gateway for 30 seconds and plug it back in. As asked, do you have any equipment between the gateway and dvr?  

I am also having the same problem as MP111.  I have nothing between the gateway and receiver.  ATT has replaced both the gateway and the receiver/DVR.  Problem still exists; however, my wireless receiver works fine.

This problem came out of nowhere.  I have had this service for the past 10 years without any troubles then, a few weeks ago the channel freezes and I get the “you are not connected” screen.

Seems like the next step to try is another wired connection to the affected receiver 

gr8sho, I tried a different line from gateway to dvr jack...same problem.  I tried a different patch cable from dvr jack to dvr...improved (signal doesn’t completely stop); but, now signal is “jerky” (stops and starts).

Uh... what?  Preparing to update with a SPAM link?

I have same problem but only on Fox News Channel. Sounds a bit suspicious to me. Would appreciate an answer

@epWest , to be sure we're talking about the same problem:

You can tune to Fox News Channel, it shows the channel for a few (normally about 10) seconds, and then goes black.  All other channels work fine?

@salma3201 , this is not Anon234853's post, and his post was made 2 years ago, so I'd suggest you open a new question and tell us all about your problem.

I have the same problem as Mp111. Tech came out and replaced all my equipment even added a grounding block, still same problem exists. Called the tech back and got no response at all !!!! Called AT&T and they tried to have me reboot everything so I did but no change and no help this is ridiculous. I've been a customer for years but this is pushing me to the brink.I pay a lot of money for a service that is more aggravating than what it's worth.

Okay, @Jimbo87 , so your service was working fine, then suddenly started doing this?

Can you please describe how all our AT&T IPTV Equipment is connected to the Gateway?  (include switches, routers, etc.)