User is unable to connect Outlook 365 with Core.
This can happen if you are connecting to a Microsoft Exchange account and your admin controls your email settings. In this case, when you connect Core with Office 365 for the first time, you will get a prompt saying, Need Admin Approval. In case you are not the admin, you will have to send a request to your Core administrator to allow Core to integrate with your Office 365. The administrator will be required to give consent. This consent allows Core to connect to your Office 365 account.