Apache 2.4 Transparent mode failure

I get the following error with the setup below: clientconnect Transparent mode failure: OSError(92, ‘Protocol not available’) clientdisconnect

Steps to reproduce the problem:
  1. Debian 9 with Apache 2.4 which listens on port 80 and 433 with SSL cert and uses proxypass to reroute traffic to localhost:8080
  2. mitmproxy 4 listens in transparent mode on port 8080
Any other comments? What have you tried so far?

When mitmproxy listens directly on these ports, no problem occurs. Do you have any hints whats going on here?

System information

Mitmproxy: 4.0.1
Python: 3.6.4
OpenSSL: OpenSSL 1.1.0h 27 Mar 2018
Platform: Linux-4.9.0-6-amd64-x86_64-with-debian-9.4