Try looking in nmis.log for escalate and mail related messages.
[root@poller-office ~]# egrep -i 'mail|escalate' /usr/local/nmis8/logs/nmis.log 04-Jan-2019 22:13:02,nmis.pl::sendMSG#8173[29711]<br>Error: Sending email to hero@localhost failed: 999 connection to 127.0.0.1, port 25, ipproto , failed: Connection refused 04-Jan-2019 22:13:26,nmis.pl::sendMSG#8173[29835]<br>Error: Sending email to hero@localhost failed: 999 connection to 127.0.0.1, port 25, ipproto , failed: Connection refused
It's also useful to manually run an escalate with a debug in order to see what's happing. Timing this with an event will be more revealing. In the following example examine the generated file for mail related information.
/usr/local/nmis8/bin/nmis.pl debug=9 type=escalate > /tmp/escalate.txt
Hello Team,
We got situation here that in a group all of sudden none of the Nodes are sending any mails configured contacts when nodes are down
If i try to add a new node to same group it sends the Node down notification but not working for list of nodes configured earlier .
i dont find any outages scheduled .
Please help me in finding the issue .