O365 – Error when creating a Sitemailbox

When creating a Sitemailbox in O365 you may receive an error while the mailbox is created such as:

The site mailbox couldn’t be provisioned.
The property „DisplayName“ with value „Testproject “ is invalid. The value can’t contain leading or trailing whitespace.

In this case the error message is somehow misleading. Yes, tailing white spaces are not allowed but in this case the title of the website is „Testproject & Co“. After a little research I found out that the error is caused by the ampersent „&“ within the site title.


The ampersent in the title is not escaped when set as parameter in the url for the sitemailbox creation. This leads to a systemside missinterpretation of the URL as an „&“ is used for seperating parameters in an URL.



If you remove the „&“ from the site title the site mailbox is reated. So if you want to use the sitemailbox feature be sure to not have an „&“ in your title.

To remove the & goto the site settings and click on „Title, decription, and logo“.


Change the „&“ into something meaningful …


…such as the word „and“.


After saving the change you can try to recreate the sitemailbox. And voilà – the URL parameter is correct and the site mailbox has been created.



I have also checked if there are other special characters such as $(){}/., that might cause this error but all other characters worked well.

If you find any other characters please let me know.


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