How can I resolve a 452 4.3.1 Out of Memory Error on the SMTP Service?

Keywords:

If you encounter a 452 4.3.1 Out of Memory Error coming from queued mail items, it is related to the SMTP service crashing on the server that is responsible for sending mail for that particular email queue. To resolve this error, restart the Simple Mail Transfer Protocol service on the server that is sending mail for that queue.