Zabbix Queue for Proxy items

[randd0]

I have a very small Zabbix environment monitoring two locations. The Zabbix server side has no performance issues. The Zabbix Proxy side has persistently queued items, anywhere from 0-80 on average. I do send traffic through stunnel from the proxy to the server. I did have a time sync issue, the server and proxy were out of sync by about four minutes. I've corrected that issue. While I can see the details of what's queued as it pertains to items on the proxy side, I do not know how to fix it. This environment has been in place for about a year, and I haven't noticed this issue prior to today. I have also been receiving alerts for zabbix busy alterter process over 75%. From a resource perspective, neither the proxy nor the server are struggling. Please advise.

Zabbix server 2.4.5-Monitoring 77 hosts, 1343 items, 17.88 new values per second.

[randd0]

I wanted to provide an update on stunnel and zabbix. I've had trouble for quite a while with the queue getting very backed up. The proxy busy data sender process was always high. It turns out the extra overhead added by stunnel caused me problems between the zabbix server and proxy separated over the internet. I switched to running the proxy over a site to site vpn between firewalls, and the problem has gone away. This may not happen for everyone, but it definitely caused issues for me.