I have a case that I do not really understand. Please help me.
I have a backend(Fargate) and frontend(Fargate). I use same ALB but different listener port to pass traffic to those instance. FrontEnd is using port 443, backend is using port 444.
I also setup the same certificate(ACM) for both Listener.
I also created record in Route53 to route to my ALB.
I also setup inbound rule to accept 443 and 444 from everywhere in the security group.
The problem is:
Everything worked find with DNS of ALB. But when using custom domain, only Frontend work with custom domain, but Backend not. Actually, I tried to use the DNS of ALB for Backend(health check api) and it's still working. But when I change to custom domain, it doesn't work.
So what is possible reason for this case. Can someone help me?
Sorry everyone. In my case, I found that there is a setting on CloudFlare that already blocked port 444. Thank you guys for you supporting.