Hello Tracey_H ,
As Kraziel mentioned, our environments havent changed, MYOB has just stopped sending emails in the fashion it used to in these environments.
Eg. previously you would "see" the Outlook integration occur, eg MYOB creating a new email and sending it, but now I am not seeing this, as if the sending process is happening in the background as opposed to in the foreground.
I think something fundemental has changed with the process in a recent update. Eg I also started to get the Outlook automation prompt 'a program is trying to send email on your behalf' and you have to click 'ok' where as we were not seeing this before.