When signing into the new Microsoft Edge browser using a workplace (Azure AD) account it displayed the following error: "Your system administrator has not granted sign-in permissions. You can try another email address or contact your system administrator for more information."

This was due to the group policy setting below being set to a value which did not match the user account trying to sign in.

User Configuration -> Policies -> Administrative Templates -> Microsoft Edge -> Restrict which accounts can be used as Microsoft Edge primary accounts

Correcting the policy allowed sign in and sync.