Redirect 9001 was not on apache
On heu2 we have SSL since quite a while. It seems we forgot to change the routing of http requests to port 80 on heu2. All http requests were forwarded to port heu2:9001 from heu0:80 with IP http://188.8.131.52/
We did not recognize it as most browsers try an https automatically.
- I put etherpad on port 9002.
- I added Listen 9001 to /etc/apache2/ports.conf
- http vhost listens now to port 9001 and does the redirect to https as expected.