A while ago I wrote a blog about finding the Content Type Hub in SharePoint Online. This site collection should be accessible for all Office 365 Global Administrators. Today I actually encountered an issue where I couldn’t access the Content Type Hub while I had the Global Administrator permissions.
Thanks to the great support of Microsoft we found a workaround to provide access:
Just replace tenantname with your tenant name (DUH ;)) and you are able to assign yourself as site collection administrator to the Content Type Hub.