wolf-server connect redis error about wolf HOT 2 CLOSED

the APISiX give the 401 response with body:

{"message":"request to wolf-server failed, err:closed"}

the apisix-rbac plugin connect wolf with HTTP1.1 keep-live but when Use the connection the connection is close

from wolf.

023/08/17 07:59:09 [error] 44#44: *38703924 [lua] wolf-rbac.lua:324: phase_func(): check_url_permission({"status":500,"err":"request to wolf-server failed, err:closed"}) failed, res: {"status":500,"err":"request to wolf-server failed, err:closed"}, client:xx.xx.xx.xx, server: _, request: "GET /emis-api/v2/inventories?_t=1692259147634&name=&inventoryType=2&page=1&size=10 HTTP/1.1", host: "xxx.com", referrer: "http://xxx.com/"

why？ the apisix rbac plugin check the permission fail ！err:closed The http connection keep-live do not match with wolf-server ?

from wolf.