Hello Rich Bund,
Normally, if we encountered any sync issue, we can use “Reset Account” option, after clicked –on it, Outlook will be forced to restart and sync items and settings from server to client.
In my view, it keeps the current connection to server and is more convenient in comparing with removing the whole account. Removing account and re-adding will make Outlook connecting to server again and perform the syncing.
To better help you and provide more specific information, I suggest you contact our dedicated support team via built-in feature: Get in-app help for Outlook for iOS and Android.
Best Regards,
Anna