Unauthorized with JWT Token called from apisix

Dear all, i config apisix routes to api /protocol/openid-connect/token of Keycloak, but it’s token not working to authen, i saw issuer from apisix instead of keycloak when decoding JWT token.
I want to know to config keycloak accept issuer from other resource like Apisix (just differ port)
Hope for support

I found solution: call api confi route with rewrite proxy in apisix
It returns jwt token with issuer as keycloak domain.
Config like that:

"methods": ["POST"],
        "plugins": {
          "proxy-rewrite": {
            "regex_uri": ["/xxx/token", "/realms/apisix_test_realm/protocol/openid-connect/token"]
          }
        },
        "upstream": {
          "type": "roundrobin",
          "nodes": {
            "xxx:8080": 1
          },
          "scheme": "http",
          "pass_host": "rewrite",
          "upstream_host": "xxx:8080"
        }
      }'