We just had a need to provide access to a shared mailbox to student users who have mailboxes in Office 365 (O365).  We have tried to do this, or something similar, in the past and had mixed results.   For instance, it would work for access to a user mailbox but it wouldn’t work for a shared mailbox.  Additionally, the O365 user would have access through an Outlook profile but wouldn’t have access through OWA (https://mail.ufl.edu/owa/[email-address]).

Because of the recent use case we have worked through the issues and have it working now.  Make sure to set the following on the shared mailbox:

1. Insure that the [alias]@uflorida.mail.onmicrosoft.com email address is on the shared mailbox.
2. Insure that the [alias]@ufl.edu email address is on the shared mailbox.  The [alias] MUST follow the format of [UNIT]-[Name] where [UNIT] is your UFAD prefix, the dash (-) character must exist, and [Name] is the specific name for the mailbox.  The @ufl.edu address will not work for email delivery unless you enter a ticket with UFIT (again, the address is only supported if you follow the correct format).
3. Update the UserPrincipalName (UPN) of the object to [alias]@ufl.edu.

Changes between UFX and O365 take up to an hour to sync to the cloud.  By doing this the students (O365 mailbox users) should be able to access the UFX shared mailbox through OWA using the https://mail.ufl.edu/owa/[email-address] URL.  If there are continued problems after making these changes it may be necessary to convert the mailbox back to a Regular mailbox so the user object is no longer disabled.