Question: eramba behind a Web application Firewall - update screen grey out


For my collaborator to work from home I have eramba setup behind the firewall (OPNSense) and use the Web application Firewall , I create a virtual external server call (public) reachable over HTTPS, only persons with a client cert can enter. on the backside I setup eramba with plain http. internally eramba works fine.

so from outside with HTTPS to my WAF and intern from WAF to eramba by HTTP

don’t understand why i can see all the screens but updating gives me a grey screen and error in the browser console

From outside I can login, see screens but as soon as I add something and save the screen turn grey
and the browser dev console gives me the following error:
Mixed Content: The page at ‘h t t p s://’ was loaded over HTTPS, but requested an insecure XMLHttpRequest endpoint ‘h t t p://’. This request has been blocked; the content must be served over HTTPS.

Can someone help me please