Why can't I add members with the same server port to my ALB?

Use the following information to troubleshoot an error message that appears when back-end members with the same server port are added to your ALB.

An error message displays when you try to add two back-end members with the same port to the same pool within an ALB. In this case, the error reads, "An instance exists with the same IP address and port value".

You cannot add two back-end members with the same port to the same pool within an ALB to avoid conflicts in ALB traffic routing. However, you can add the same back-end member with the same port in different ALB backend pools.

Choose different ports for the members in your NLB's back-end pool for your NLB to function properly with a passing health check. You can add the same member with different ports within the same pool.