Nest Thermostat/Protect OAuth - NestOAuthAPI problem while changing router to Unifi

[dre68]

I changed my (Telfort glasvezel) Experiabox V8 router to an Unifi USG router to complete my Unifi eco system. Since that moment I am getting NestOAuthAPI errors and the thermostat is not working anymore (in Domoticz).

NestOAuthAPI: Login failed: token did not validate.
NestOAuthAPI: Error while performing login: Got empty response body while getting structures.

Is there someting specific I have to set up in the USG router to facilitate the nest api to communicate outside the LAN?

If I put back my old Experiabox as router, the Nest Thermostat/Protect OAuth hardware item starts working properly again

Any ideas what could be the culprit?

[dre68]

For those who concern, I have found the solution to this issue myself (for Nest thermostat with Nest account).
It seems that the Ubiquity USG router has a tighter firewall than the Experiabox V8 my ISP provided.
You have to forward port 9553 to the Domoticz IP adress, this to let Domoticz transmit and receive data to and from the Nest API server.

Everything is working fine now.