@tehmilcho just remove “cors” from your config.json. Then this error is gone. More info here: https://forum.pimatic.org/topic/2081/missing-property-allowedorigin
If you using apache with ssl you also need to add the ssl certificates to apache config.
Is there a reason why how using apache2 instead of nginx for reverse proxy?
I`m using nginx with this config: https://forum.pimatic.org/topic/1199/pimatic-through-reverse-proxy/5
Maybe give it a try