@WayneD42 

Is the ooma connected via wifi or ethernet?

If ethernet, try a different cable and a different port on the router. Be sure to power cycle between changes. Also be sure you are using the power adapter that came with the router and not the one from the old router.

  @ArcherC8 It's connected via Ethernet. The same ethernet setup that works great connected to literally any other router. The new router is working fine for other things. It just interferes with VOIP.

  @WayneD42 

are you using QoS as that may be the issue.

you can also connect the ooma between the modem and router. 

  @ArcherC8 I don't use QoS. I can't put the Ooma anywhere but behind the router, because my router is the thing getting the IP from my ISP. I could put another router in front of the tp-link, but I'd rather the tp-link do its job correctly.

This is a bug report to the tp-link folks for something that they need to fix. Is there a better way to let them know that this is broken?

  @WayneD42 

The ooma can be installed between the modem and router. No change to router. Router still does the ip. See the alternative network settings in the install guide.

google " ooma telo setup between modem and router" for the pdf guide.

I used that before my internet speed and service improved. 

  @ArcherC8 Thank you for hammering that info home with me. I didn't realize that I could chain the router through the Ooma Telo.  The Ooma does indeed work this way, as it then gets the public IP from the ISP and gives a 172.* (local network) IP address to the tp-link.  This would presumably put a crimp into any advanced router setups where someone wants to manually configure an open port on the public IP address (since the router isn't handling the public IP anymore), but perhaps UPnP will auto-forward through the extra NAT device.

  @WayneD42 I connected the Ooma Telo between Xfiniti Modem and TP Link Router, but no signal to the router at all, and the Ooma Telo doesn't work too.

  @RayIam 

Does the router work okay without the omma in between?
Does the ooma work when attached to the router?

Have you tested the cables?