WebRTC Phone "Can't provide secure audio requested in SDP offer"

Hi Everybody,

does Somebody can help me with below Problem?

When I try to make a call with the Webphone in the User Control Panel, I get below Error Message.:

chan_sip.c:10427 process_sdp: Can’t provide secure audio requested in SDP offer

I’m logging on with https:// to my UCP by using and Let’s encrypt Certificate.
All looks godd, except this little issue shown above.

Calling with Webphone works well with http:// but I need to use https:// …

thanks for your help, NUB