Issue: Etherpad Integration on Ubuntu 18.04

Hey folks,

we have installed Etherpad on Ubuntu 18.04 with this manual: https://www.howtoforge.com/tutorial/ubuntu-etherpad-editor-server-installation/ but without reverse Proxy.

We configured etherpad_base: ‘https://mydomain/etherpad/p’.
We tried a lot of different options.

We can reach Etherpad with localhost:9001 but when we try to open it in Jitsi, our connection get refused.

The browser console shows the following errors:
<Object.getGlobalOnErrorHandler>: UnhandledError: Uncaught SecurityError: Blocked a frame with origin “mydomain” from accessing a cross-origin frame.
Line: 152 Column: 124372 StackTrace: DOMException: Blocked a frame with origin “mydomain” from accessing a cross-origin frame.

Anyone here that can help us?