http 500, 'timeout / couch_config, get "admins" '

Binary package hint: couchdb

it caused HTTP 500 and couchdb described it as
{"error":"timeout","reason":"{gen_server,call,[couch_config,{get,\"admins\"}]}"}
{gen_server,call,2},
             {couch_server,has_admins,0},
             {couch_httpd_auth,default_authentication_handler,1},
             {couch_httpd,authenticate_request,2},
             {couch_httpd,handle_request,5},
             {mochiweb_http,headers,5},
             {proc_lib,init_p_do_apply,3}