Depending on the organization type that is being restored, the first step of the credentials dialog will be different:
When restoring to on-premises Exchange server, specify the Global Catalog server name and provide valid access credentials. You can use your current account or specify another one in the domain/username format. For more information on required permissions, see Required Permissions.
When restoring to Exchange Online, specify the account to connect to the target Exchange server. You can use your current account or provide another one in the username>@<organization>.onmicrosoft.com format. For more information on required permissions, see Required Permissions.