Doorbell won't scan code

[AT23]

I have changed router and doorbell now won’t scan code. I have split Wi-Fi and am connected to 2.4ghz. Tried phoning but no joy there. Any help to connect gratefully received. 
have followed all trouble shooting on app 

[jguerdat]

Try removing the doorbell from your account as well as resetting it:

https://kb.arlo.com/000062346/How-do-I-reset-my-Arlo-Essential-Video-Doorbell

[AT23]

Ended up phoning Arlo directly and spoke to a very competent advisor. (After an incompetent one a few days earlier). Solved in 3 mins! 
make sure internet at 2ghz and get device to forget (temporarily) 5ghz. (This was the key as I’d done everything else) Take off mobile data and Wi-Fi assist. It worked! 

[ShayneS]

Thank you for the update.