This response from support did the trick for me. I had done all of these steps multiple times, but this finally worked.
Be sure that your phone is connected to a 2.4 network. The anova app will use whatever wifi your phone is connected to.
"Greetings! Sorry to hear you’re having issues with your Precision Cooker. I’ll do my best to get you connected.
Please follow the basic troubleshooting steps below.
-Please uninstall the Anova app.
-Reset the Precision Cooker by holding the WiFi / Bluetooth light indicator (located on the touch panel) down for 3-5 seconds. You will hear a beep. Do it twice. Unplug cooker, wait the a minute then plug the cooker back in to the power outlet.
-Make sure the Precision Cooker isn’t more than 5 ft away from the router for the initial setup and all your WiFi extenders / repeaters are disabled.
-Reinstall the app, reboot your phone, enable your device’s Bluetooth, launch the app and go through the setup process again."