It seems that there is some issue with the SMTP template for Zabbix.
From the Zabbix Server , we can see that the zabbix_get returns 1 (Good):
[root@zabbix-ord zabbix]# zabbix_get -s webui1.ord -k net.tcp.service[smtp]
1
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But the SMTP Template to the get the status of SMTP service returns the Value 0, hence at the server, the SMTP service is displayed as Down
SMTP Tempate Trigger is :
{webui1.ord:net.tcp.service[smtp].max(#3)}=0