NCE Unable to Report Alarms due to SNMP Trap Command

Hello, everyone!
Today, I'd like to share a case with you.
Product Model:  NCE
Problem Description
After the devices have been successfully added in NMS Network Cloud Engine (NCE), NCE synchronization issue was observed on the devices. Due to this problem, network devices were visible on the NCE but if an interface flapped on any of the devices, then NCE did not report any alarm.
Problem Analysis
1) We have checked snmp-agent configurations on all old and newly installed devices
2) NCE IP was allowed in acl configured for snmp-agent community
#
snmp-agent community write cipher * acl 2000
acl number 2000
rule 70 permit source X.X.X.X 0
#
3) On all devices source interface for snmp traps was management/loopback interface. After configuring snmp commands, few newly installed devices source interface was changed for snmp traps and it was admin down which hinder to send trap messages to the server. Then we up this source interface but still NCE synchronization issue was not resolved and NCE was not showing any alarms that appeared on the devices.
4) Finally, we involved GTAC to further troubleshoot this issue
Root Cause
Initially the old devices monitored through NMS U2000 and then we added NCE in the network for all devices including old and new new devices. All the devices are visible on new NMS NCE but did not report any alarm if an interface up/down on the device.
GTAC team diagnosed that snmp-agent target host configuration for NCE IP  was found to be missing. The team directed to execute the snmp-agent target host  command.
Solution Description
After executing the below command for snmp target host, devices begin to respond NCE and alarms appeared on NCE.
Welcome to leave a message below.
We study together.
Thank you!