AWS ALB HTTP2 - Not working

Question

For our application, we are using Application Load Balancer in front of our AWS EC2 instances (web servers)

We're using a set of Application Load Balancers in AWS. For only one of our application load balancer, http/2 is not working. For other Application Load Balancers, http/2 is working.

We are testing by checking Network console in Chrome.

Is there any specific configuration that we are missing in our ALB ?

Welcome to StackOverflow! Unfortunately, there is not enough information in your Question to be able to give a solution. Have you checked the configuration of both Application Load Balancers to see what's different? Have you tried creating another ALB to see if it works correctly? Are you testing from exactly the same computer & browser, just changing the DNS Name to point to the other Load Balancer? — John Rotenstein
Thanks. We tried creating a new ALB and HTTP/2 started working.. Not sure whats wrong with the old ALB. It was working till 2 weeks back, suddenly it stopped working. Anyway, thanks for your suggestion. It worked for us. :) — user1021783

Hareesh R Hareesh R · Accepted Answer · 2019-07-03T09:36:32

For fixing this issue, we should check the status of instances in the target group first. If any instances are showing unhealthy, need to fix that first

AWS ALB HTTP2 - Not working

1 Answers

For fixing this issue, we should check the status of instances in the target group first. If any instances are showing unhealthy, need to fix that first

Goto the listeners in ALB and check does the route of 80/http is properly routed to the target group