When sending data to zabbix_server via the zabbix_sender command, no information is output explaining why a data item is marked as "failed", even with debug logging turned on.

It'd be helpful if the reason why an item was failed was output in the debug logging, specifically in the code in src/libs/zbxdbhigh/proxy.c

(The error I encountered was in the line:

if (SUCCEED != DCconfig_get_item_by_key(&item, proxy_hostid, values[i].host_name, values[i].key))

I have no idea why an item would not be in the cache, causing this statement to fail)