I get a lot of these incidents in my queue after a user has been migrated to O365. For whatever reason, most likely due to the mailbox being moved itself, whether it is the user’s mailbox, the shared mailbox, or both, the connections to the shared mailboxes stop working in Outlook and the user cannot connect to the shared mailbox.
Here is a quick and easy solution to use to disconnect and reconnect the shared mailbox(es) that you lose connectivity to when migrated. This is usually performed on Outlook 2016 and above as most users upgrade their client software when moved to O365.
First, we remove the existing shared mailbox connection:
- Click the File > Account Settings > Account Settings.
- Select your company email address in the account list.
- Click Change > More Settings > Advanced tab > Select the Shared Mailbox > Remove
- Click Apply > OK > Next > Finish.
- The shared mailbox will now automatically be removed in your Folder pane in Outlook.
Second, we re-add the shared mailbox connection to Outlook:
- Click the File > Account Settings > Account Settings.
- Select your company email address in the account list.
- Click Change > More Settings > Advanced tab > Add
- Type the name of the shared mailbox in the window and click OK.
- Click Apply > OK > Next > Finish.
- The shared mailbox will now automatically be added to your Folder List pane within Outlook.
Note: The above procedure must be followed in order to properly reconnect the shared mailbox. You cannot remove and re-add the mailbox in the same process as that will not reset the connection properly. You must save the settings when disconnecting.
I hope that this will assist everyone when troubleshooting Outlook connectivity issues to shared mailboxes after a migration.
