A user in my organization will sometimes experience an issue where a sent email sitting in the Outbox for some time before it is finally sent. This is for the Outlook app for Mac. Outlook on web works fine, although user doesn't use the web version often enough to notice any issues.
I also noticed that the user's Outlook app is using a lot of computer resources on the MacBook Air. At one point, Outlook app had sent over 388 MB over the user's network and over 700MB for memory (compared to Teams 150MB). The user has a new computer and I am guessing that there is a lot of email that needs to be synced on the new laptop.
So my question is - what may be causing the sent emails to sit in the Outbox? Could the large amount of resources that Outlook is using on the machine be from syncing several year's worth of email to the Outlook app? Could that cause some slowness in emails being sent?