We have had a complaint from one of our internal departments about a slowdown in email they send clients by a few hours. They send a few thousand emails out every night to the same clients.
I have looked and their server is relaying email through one of our HT servers, i have exported the message tracking logs for a few sample addresses from last night and also the week before (Monday 13th)
I have noticed that last night there is up to a 20 second delay between the receive connector receiving the email from the app server and then submitting it to messagelabes to send out as shown in print screen.
Im not sure what could be causing this or how to prove where the delay is.