Ignore this. It is a service that gives us our public IP and I block any cookies from them.
Can you connect the wires for AC and Fan together on the AC terminal on HestiaPi?
I am not sure if your system has a delay or something for the Fan when it is on AC mode.
I assume the pin assignment on HestiaPi Touch US version is correct, pin 23 is actually connected to the relay where you connect the Fan. You could check with a multimeter if the output of each relay is active (24V AC) when triggered.
You can manually control the state of the 2 relays with this:
Could the fan relay have died somehow?