When you're troubleshooting System Status error messages which are generated by the Watchdog service, it's sometimes necessary to check the security settings for the Windows SNMP Service. But you may find that when you look at the Properties for the SNMP Service, the Security tab is missing:
This is due to the fact that Microsoft Windows 2012 R2 does not install SNMP Tools by default. They are listed in the server prerequisites for installing Network Flow Analysis, but it's easy to miss it during the setup.
Open the Server Manager and go to Add Roles and Features. Under the Features section, select Remote Server Administration Tools-->Feature Administration Tools and check the box for SNMP Tools:
Hit Next, and then Install. Once the installation completes, restart the SNMP Service and then close and reopen Windows Services. When you look at the Properties for the SNMP Service you will see the Security tab: