Hi, Here are some things to check.  "DNS DRAC Name " and "Static DNS Domain Name " is configured on iDRAC Settings -> Network page, On Server->Alerts->Alerts page, can you check whether Alerts is in "Enabled" state? Is email authentication enabled? Are you using a FQDN or an ip address for the mail server?   
hello I installed ESXi 5.5 on my PowerEdge R720xd, I'd like to receive alert via email and I've updated the relevant parameters accordingly in the idrac. I can receive the test message, however, when I simulate server problem the event is triggered and can be found in the event log, but no luck to receive the same via email, what's the problem? Please share your experience.
idrac7 email alert