"An error occurred while sending email notification of a triggered alarm" event is generated even though customer configures the STMP server in vCenter.
When customer attempts to perform a reverse lookup for the IP address of the SMTP server in the vCenter, the output might result in an error like the one shown below.
# dig +noedns -x <IP_ADDRESS_OF_SMTP_SERVER> ; <<>> DiG 9.16.42 <<>> +noedns -x <IP_ADDRESS_OF_SMTP_SERVER> |
VMware vCenter Server
This issue can occur because the DNS server configured in vCenter doesn't have the specific PTR record for the SMTP server.
Reverse lookup entries of SNMP servers must be created in the DNS server for vCenter to perform the reverse lookup properly.