This article provides steps to configure a custom alarm to send an SNMP trap for the error:
Unable to apply DRS resource settings on host [hostname]...
VMware vCenter Server
Create a custom alarm in vCenter Server with the following configuration:
Navigate to Configure > Alarm Definitions and click ADD.
Set Target type to Hosts.
In the Alarm Rule section, search for and select the trigger:
Cannot complete DRS resource configuration (found under the DRS category).
Select Send SNMP traps.
Complete the wizard to save and enable the alarm.