While using Collaborative Authoring why does a user receive the error message:
Unable to add user to the edit version of this document in Microsoft Office. Please check to make sure the user [user name] has a valid account in Microsoft Office or use a different check out option.
This error indicates there is a configuration or permission issue on the SharePoint/Azure AD side of the Collaborative Authoring setup. Vault Support does not support SharePoint/Azure AD configuration at this time. Users need to work with their internal IT Department for further assistance.
Vault Collaborative Authoring Documentation: Configuring Collaborative Authoring with Microsoft Office