;tl;dr A recent attempt to share a site collection provisioned by the new "Create Site" link in SharePoint Online revealed that in order to share the site collection with external users you must change the sites "SharingPolicy" property from the default ExistingExternalUserSharingOnly to ExternalUserSharingOnly to enable new external user invitations. This must be done with the Set-SPOSite PowerShell Cmdlet The Back Story I recently had a project that required providing External User access to a newly provisioned Office 365 Group's site collection in SharePoint Online. Simple, right... Just click the Share icon on the home page, and invite the external user. Wrong! In the past, when working with clients we (ThreeWill) have provisioned a SharePoint site collection per client...
Here's some of the upcoming public events in Atlanta: