I'm currently on my second Tapo doorbell that won't work. 

My first doorbell worked just fine for a couple of months. Then I changed router (5G router) to the same model just a different unit – ZTE MC888 Ultra. After I changed router, the doorbell wouldn't configure. I get to the last step when installing but It won't configure. It says something "Internet connection is too weak. Try move closer to the router". But it doesn't matter if I'm at the door (where it is mounted) or just next to the router, it won't configure. 

Last week I returned the first doorbell and i got a new one from the store i bought it. 

During the first installment it worked fine. It seemed like it really worked. I could see live from the camera in the tapo app a few hours efter installing. But the morning after, it wasn't working anymore. It was offline. And now I get the same messege as last time when trying to re-install it. 

– I've tried to split my Wifi into two, one 2.4GHz and on 5GHz - trying to installing on with the 2.4GHz.

– I've tried resetting the device, the router and deleting the Tapo app in my phone. Nothing works. 

– I've tried to press and hold both SYNK/RESET and Anti-theft buttons simultaneously for 10 seconds. It does the same thing as if i was just pressing and holding SYNK/RESET.

While ON, it "double-blinks" red a few times, then steady amber for like 10 seconds, then red again. 

What should I do?