I just synced my Office 365, but my past emails did not come in. Why not?
The initial sync will bring in your sent messages from the last 45 days, or the most recent 80 messages (whichever comes first). It will bring in your most recent 100 received messages, or received messages from the last 45 days (again, whichever comes first). The sync does not bring in all of your historic emails but will sync all email sent or received in Office 365 going forward.
My Office 365 email sync was working but now I'm getting an error.
The most common reason for these errors is that your Office 365 password has changed but has not been updated in Nutshell, but this could also happen for other reasons. Either way, resetting your sync usually fixes this. Follow these steps:
Go to this page and revoke access to your Office 365 account by clicking "Disable", then "Forget this account and add a new one", then "Disconnect".
Re-enable access and follow the steps to get reconnected in the wizard.
Once you've done this, you should be able to click "ignore" on any visible errors to clear them.