Recently found my autosupport mail was undelivered. The config was follow exactly with the working one. So after digging for few days and finally i found the root cause. there is one file *.ems.gz is about 30MB and caused the exchange server to block it. (Thank god 1 of the triggered mail received)
Netapp support had send me the instruction to rotate the log files:
priv set advanced
ta.da……..problem resolved and you are able to receive all autosupport now!