With IPHost Network Monitor you can run simple snmp requests against a Fortinet device in your network.
fgApPOP3StatsTable
fg Ap POP3 Stats Table
1.3.6.1.4.1.12356.101.10.102.3
A table of POP3 proxy statistics per virtual domain
Back to FORTINET-FORTIGATE-MIB MIB page.
IPHost Network monitor allows you to monitor fgApPOP3StatsTable on Fortinet device via the SNMP protocol. Download IPHost Network Monitor (500 monitors for 30 days, 50 monitors free forever) to start monitoring Fortinet access points right now.