Definition

Site Mailbox

A site mailbox can be used from a SharePoint team site to store and organize team email. It can also be used from Outlook 2013 for team email, and to quickly store attachments and retrieve documents from the team site.

https://support.office.com/client/Add-a-site-mailbox-cccaa235-c611-48e3-9653-0b9e161840e7 

You can add one site mailbox per site.

Stuck

It sometimes does happen that a site mailbox is not created properly and all troubleshooting steps failed. 
One of the symptoms may be this error message appearing for several days:



All you need to do is remove the site mailbox and add again.

Remove 

In order to thoroughly remove the site mailbox app follow all of the steps below in that order.

From User Interface

1. Try to remove the app from the User Interface.



This may or may not work at this stage. If you receive an error - do not worry.

From Powershell

1. Open Powershell with Azure Active Directory Module installed and connect to Exchange Online.

2. Check if the mailbox has been created using the cmdlet:

Get-Mailbox  SMO-SITENAME

Where SITENAME is the title of your SharePoint site. If you receive an error that a mailbox could not be found, do not get discouraged. It could have been malformed with a different name.




3. Verify all your site mailboxes:

 Get-Mailbox -RecipientTypeDetails Teammailbox

If you have a lot of site mailboxes, you can try sorting by date created (so that the recent ones are at the bottom):


The corrupt name may look like SMO-RN70789.

4. Remove the mailbox using

Remove-Mailbox SMO-RN70789

or

Remove-Mailbox SMO-SITENAME

and verify if it is gone from the list of all mailboxes:


5. This, however, may not do the job.  Check if you still have a user of the same name, using:


6. If the user is on the list remove him and then remove that deleted user from the recycle bin.



7. Verify if the user is gone from the list:

From SharePoint Designer

1. Download and install SharePoint Designer.

2. Open your website in SharePoint Designer.

3. Click on Site Options>a dialog box should appear.






4. Choose 4 features related to Exchange Mailbox: 

• ExchangeTeamMailboxEmailAddress
• ExchangeTeamMailboxSiteCollectionUrl
• ExchangeTeamMailboxSiteID
• ExchangeTeamMailboxSharePointUrl) 

and remove them.




 


The steps are also available using CSOM and Powershell

From User Interface (again)

Go back to your site and remove the app from the User Interface. If it didn't work before, it should work now. In the unlikely event that it should still pose some problems, please paste the error message in the comments and start a question thread on the Sharepoint MSDN forum.

Create a new site mailbox

Now that your site mailbox is safely removed, you may want to add a new one.

You can do it from the User Interface or from Powershell:

Errors

When creating a site mailbox you may encounter the following errors:

• Unauthorized

Solution: Verify the site URL.

• Windows Live ID already exists

That means that the mailbox has already been created in some way, e.g. when I misspelled the SharePoint URL.
Solution: Find the user and remove him.

 

• Site Mailbox app hasn't been installed

Solution: Verify if the site mailbox feature is activated under Site Settings>>Site Features>>Site Mailbox>>Activate

Scripts

 Scripts for creating site mailboxes via Powershell:

• Add Site Mailboxes to all site collections and subsites on the whole tenant
• Add Site Mailbox to a site collection and its subsites
  
• How to add a site mailbox to SharePoint Online site programmatically

Other Languages

This article is available also in other languages:

Wiki: SharePoint Online: Jak usunąć skrzynkę witryny oraz często występujące błędy przy tworzeniu nowej skrzynki (pl-PL)