Currently my company using Office 365 GCC High for all our everyday work. Email, SharePoint (Internal Collaboration), Skype, etc. We have an old Office 365 Enterprise account that our users use to do some proposal work that requires them to collaborate with outside partners, consultants, and contractors. I understand not allowing our O365 Enterprise accounts to login to O365 GCC High, but to not allow our GCC High accounts to login to Enterprise is a bit baffling to me. I can use my GCC High to log into other GCC High things that Microsoft provides like their Enterprise licensing portal or Microsoft Azure (non-government version). I have verified that it is not the government version as none of our Azure Government resources are visible and I have branded them differently. This causing not only issues with licensing twice for Office 365 services in two different clouds but by nature if we want to do any collaboration with anyone outside of GCC High, we have to use a private account or one in our 365 Enterprise environment.