Error with Google Home integration (via duckdns) after OTP setup

Hello all

I followed the guide and I integrated Home Assistant with Google Home, exposing HA via duckdns and it was working properly

I don’t if it is the root cause, but I enable the OTA in HA and after it Google Home stop to work.
So I removed the OTA, but now still issues (every command gives an error)

I unlink the project and not I am getting timeout error or other error when adding the integration try to contact the HA URL

Note: if I call the URL direct from browser, it is ok.

do you have any idea?
I am getting crazy

Regards
Claudio