@David-TP Thanks for the response.

I don't think the iPad is the problem.  I just used that as an example.  I actually have four different model iPads connected to this network and all of them do not work.  The problem is also not restricted to the iPads.  I just used them as an example.  I have several televisions that are connected to the Deco and they do not work either.

I have done just about every combination of guest network configuration on the router including changing every setting imaginable.  The devices all have no problem connecting to the Deco and they all get an IP address that is in the correct subnet.  They just cannot access the Internet reliably after connection.

To reiterate, the Deco worked perfectly for a year.  Nothing changed except that I switched Internet providers. That in itself should not have caused any problems. The Deco got a new WAN address and all wired devices seem to be working fine.  No drops, no lost packets, etc.  The problem is only with the wireless devices.

I think the next step will probably be to hard reset all of the Deco devices.  All I can think of is that somehow the WiFi is still trying to route through the old gateway or something crazy like that.  I have had problems in the past with restrictions that I delete still staying in effect so there are definitely some bugs in the firmware.  

  @David-TP I finally bit the bullet and did a hard reset on the Deco, but unfortunately it still does not work.  Now the Wifi connected devices either connect to the Deco and report no internet access or every site I try to access tells me connection reset or unable to establish SSL connection.

I even tried taking each of the three units and resetting them and configuring them as the main deco.  I had the same result on all of them.

It looks like my $300 Deco system has become an expensive paperweight.

  @David-TP 

 I switched from Suddenlink cable to Frontier fiber.  The fiber connection is through a Frontier ONT model number fox222.

I have tried switching the DNS to 8.8.8.8 and to several other DNS providers at both the router level and at individual devices.  It makes no difference.  I didn't really expect that to be the problem since all wired devices work perfectly using the same DNS and Internet connection.

The Wifi problem is not isolated to one or two devices.  Every device in my home that is connected to Wifi is not working.  Intermittently on the iPad I will get something that comes in over the Wifi like a Google Chat message which makes me think that the Internet is not completely blocked.  When I try to browse the Internet on the iPad I will either get a message that is could not negotiate SSL or that invalid data was received causing a break in the connection.  No pages will ever display.

I will try to get a video from the iPad and send it to support.

  @David-TP 

One other thing to note with this is that I have another router that I hooked up because I needed Wifi and it works perfectly.  I also talked to Frontier and they said they do not require MAC cloning or any other setup at the router level.