[pAno]

It looks like I spoke too soon. If you don't send an email for a while it errors on the first one. If you then retry it works fine however and subsequent emails also work fine.

[40700] (12/17 11:59:30.477):{0x4A54} {user@domain.com} Receiving packet from device, size=133, TransactionId=-2145811, Tag=541946, content type=CMIME, cmd=0x3
[30112] (12/17 11:59:30.477):{0x4A54} {user@domain.com} Receiving message from device, RefId=560465, Tag=541946, TransactionId=-2145811, Date=17/12/2015 11:59:26
[20265] (12/17 11:59:30.597):{0x4A54} {user@domain.com} MAPIMailbox::Send(ppMAPIMessage) - SubmitMessage (0x80004005) failed
[20472] (12/17 11:59:30.637):{0x4A54} {user@domain.com} Send() failed: ERR_SUBMIT_MAIL, RefId=560465, Tag=541946
[40277] (12/17 11:59:30.637):{0x4A54} {user@domain.com} Sending message error to device for message 560465
[40583] (12/17 11:59:30.637):{0x4A54} {user@domain.com} Sending packet to device, Size=44, Tag=2479749, TransactionId=-697131