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Is it possible to create a completely unique URL for a Workspace 365 environment?

This is possible for parties which host Workspace 365 themselves (server-wise). Contact your specific reseller to discuss if this is possible. If we (New Day at Work B.V. - Workspace 365) are hosting your Workspace, this is also possible. 

Make sure you have a valid certificate (.pfx) for the URL you want to bind to the Workspace. Contact  support@workspace365.net  for more information.