OnlyOffice Connector Configuration/Installation


can someone help with the Configuration of Onlyoffice Connector and Onlyoffice Community server ?

I tried several configuration options, but no one is working.
Easiest config is to set up a docker image of onlyoffice and a docker image of xwiki, then install the connector and have a try.
With the docker images this is a tracable config and there are not much options to do wrong.
Onlyoffice is working with the example page, and xwiki is also working fine. Both with official certificates, but the connector has java errors, or loading forever or has CORS error. With the demo server the connector works.

So this must be a configuration problem, but even the support of the PAID connector can not give me a working example config.