failed to run balancer_by_lua*: /opt/verynginx/openresty/lualib/ngx/balancer.lua:118: bad argument #4 to 'ngx_lua_ffi_balancer_set_current_peer' (cannot convert 'nil' to 'int')

[junweigu]

failed to run balancer_by_lua*: /opt/verynginx/openresty/lualib/ngx/balancer.lua:118: bad argument #4 to 'ngx_lua_ffi_balancer_set_current_peer' (cannot convert 'nil' to 'int')

一直报这个错误，请问怎么解决？》

[junweigu]

stack traceback:
[C]: in function 'ngx_lua_ffi_balancer_set_current_peer'
/opt/verynginx/openresty/lualib/ngx/balancer.lua:118: in function 'set_current_peer'
/opt/verynginx/verynginx/lua_script/on_banlance.lua:13: in function 'run'
/opt/verynginx/verynginx/lua_script/on_banlance.lua:22: in main chunk while connecting to upstream, client: 43.227.137.3, server: test.uso.cn, request: "GET /favicon.ico HTTP/1.1", host: "test.uso.cn", referrer: "https://test.uso.cn/"