N3000 logging emails

Unlike our N4000 units which send logging emails we can't get our N3000 units to do so.  We keep getting the following error message:

<189> Oct 5 02:11:58 ml-k-idf1-as-3048p-6-1 TRAPMGR[EmailAlert]: traputil.c(763) 14166 %% Email Send Failed!No of Email sends Failed So far= 1671

We even get them when trying a test.

logging email test message-type both message-body "test message 1"

The N3000 mail server configuration is identical to that we're using in the N4000. 

Firmware is 6.3.2.4.  Suggestions?