Can't connect new oven to app on android

I made a guest wifi account on my router for 2.4GHz WPA.
Connected my android to that account.
Type in 4 digit number from oven handle
App tries to connect, then kicks me back to the 4 digit code screen with a “retry” button.
We’ve had this oven for 6 hours and we both hate it.
Customer service won’t respond to my questions.
If we can’t connect to the app, it’s getting returned under warranty.
Anything else we can try?