In order to install the Insightly add-in for Outlook, you must have the following:
- An Outlook client that supports add-ins
- Outlook online or Outlook desktop 2013 and higher
- An Office 365 business subscription that is not provided through a third party, like GoDaddy or Rackspace
If you have an Insightly for G Suite account and access your Gmail through Outlook, you won't be able to use the Insightly add-in.
If you are having issues with Outlook admin permissions during the installation of the app, please contact Microsoft Support for assistance.