Pivotal integration 6.0 for Microsoft Outlook could not be installed.
You can't install the application because it's possible that the version you have to lack compatibility with the Outlook. I've found Pivotal to be compatible only with Microsoft Office 2013 and 2016. You can obtain additional information from the link posted below.
Office Store: https://store.office.com/en-001/app.aspx?assetid=WA104379833&ui=en-US&rs=en-001&ad=US&appredirect=false
If you have questions, contact the developers although they are in another league.