Help Center/ Elastic Load Balance/ FAQs/ Listeners/ Why Can't I Select the Target Backend Server Group When Adding or Modifying a Listener?
Updated on 2023-03-30 GMT+08:00
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Why Can't I Select the Target Backend Server Group When Adding or Modifying a Listener?

The backend server group's protocol (backend protocol) you want to select is not supported by the listener's protocol (frontend protocol). There are some constraints on the backend protocol when you associate a backend server group with a listener.

Table 1 Frontend and backend protocols of dedicated load balancers

Frontend Protocol

Backend Protocol

TCP

TCP

UDP

UDP/QUIC

HTTP

HTTP

HTTPS

HTTP/HTTPS
Table 2 Frontend and backend protocols of shared load balancers

Frontend Protocol

Backend Protocol

TCP

TCP

UDP

UDP

HTTP

HTTP

HTTPS

HTTP
Parent topic: Listeners