Am following "Perform a Google Workspace (formerly G Suite) migration" instructions and am now at the step "Provision users in Microsoft 365 or Office 365".
Am attempting to create Mail Users, in order to add the external email address "userXYZ@gsuite.mycompany.com" to my active users, as well as the proxy/alias email address "userXYZ@o365.mycompany.com", as described in the instructions to the normal email address "userXYZ@mycompany.com".
Am getting the "Create contact failed" with "Error: The email address is already being used. Please choose another email address." I am assuming that is because there are active users with normal email address "userXYZ@mycompany.com" (with Microsoft 365 Business Standard license).
How can I add the required email addresses, to my active users, please, so I can continue with the migration process?
Does the process work with active users? Are Mail Users different from Active Users?
Would I need any special rights to add these two additional email addresses to my active users?
Any input would be greatly appreciated. My company really wants to move away from Google and over to Microsoft, but of course would like to migrate their existing emails.