Hey, you put the http and the https proxy port to 80. is that correct? perhaps it should be 80 and 443?! just guessing.
Regards.
EDIT
I have never set any proxy ports - and xwiki runs just fine with haproxy.
my java_opts:
- JAVA_OPTS=“-Xmx2048m -Djava.awt.headless=true”
EDIT 2
Welcome to the community 