This guide applies to the following error Excel Online users may see when trying to install the Supermetrics for Excel add-on:
Your administrator has not installed Web Add-ins for your organization
This error generally means that your O365 system administrator has disabled the ability for users to install add-ons. You will need to contact your system administrator to either change your account permissions to allow you to install add-ons or have them install the add-on globally for you to access.