In UW Office 365 Exchange Online, you can give other users access to your personal mailbox (aka email account) or other mailboxes you own (e.g., Shared UW NetIDs with UW Office 365 accounts). You can also grant Exchange-enabled UW Groups access to your personal mailbox or other mailboxes you own. All members of an Exchange-enabled UW Group will have the mailbox permissions assigned to the UW Group. Once a user/UW Group has access to another mailbox, depending on the permissions granted they can:
These permissions are granted and managed using the Provisioning Request Tool (PRT). Once permissions are granted, a supported Exchange Online client can be used to access another mailbox.
Use the PRT to manage UW Exchange Online mailbox permissions for UW NetIDs you own
With these mailbox permissions, a user effectively has full control over the other mailbox and can read all of the email in the mailbox and send email as the mailbox. The recipient of an email sent by a user using Full Access & Send As permissions on a mailbox will not be able to tell the email was sent by any other account other than the mailbox itself.
With these mailbox permissions, a user can read all of the email in the other mailbox. A user cannot, however, send email as the mailbox.
With these mailbox permissions, a user can send email as the other mailbox but cannot read any of the email in the mailbox. The recipient of an email sent by a user using Send As permissions on a mailbox will not be able to tell the email was sent by any other account other than the mailbox itself.
With these mailbox permissions, a user can send email on behalf of the other mailbox but cannot read any of the email in the mailbox. The recipient of an email sent by a user using Send on Behalf permissions on a mailbox will see that the email was sent by the account using Send on Behalf permissions on the other mailbox.
Once a user has been granted additional access to another mailbox, they can access that mailbox several ways using a supported Exchange Online client.
After you complete this procedure, the other mailbox that you have access to will display in your Outlook on the web folder list.
If you decide that you no longer want to see the other mailbox in Outlook on the web, right-click the folder and click "Remove shared folder".
If you do not want to add the other mailbox to your folder list in Outlook on the web, you can open the other mailbox in a separate browser tab.
After you complete this procedure, the other mailbox that you have access to will be listed in your Outlook for Windows folder list.
After you complete this procedure, the other mailbox that you have access to will be listed in your Outlook for Mac folder list.
After you complete this procedure, the other mailbox that you have access to will be listed in your Outlook for iOS or Android app.
You are receiving this error because the UW Group you added is not Exchange-enabled. Learn how to Exchange-enable a UW Group. After you've Exchange-enabled the UW Group, wait 2 hours then refresh the PRT and you can add the UW Group to be provisioned with elevated access to a mailbox.
Adding multiple mailboxes to an email client is resource intensive and can cause unexpected issues. For this reason, we rely on Organization Exchange Support Groups (OESGs) to support Outlook configurations with multiple mailboxes. For users without an OESG, we recommend adding additional mailboxes in Outlook for the web.