Does Sngine 3.2.1 work behind an Haproxy reverse proxy?

I have LXD containers with various websites. I use haproxy to route to the correct container and website using sub domains. For Sngine I use subdomain as the URL and it does route to it but fails with about a dozen errors like this: 12:00:31.934 Blocked loading mixed active content “”

It should probably be but how do I fix that?

I have installed an SSL cert but that does not help. Ideas?

I need to know if Sngine should work behind the haproxy?

Problem fixed with the following haproxy setting:

reqadd X-Forwarded-Proto:\ https if { ssl_fc }