The account "Service" is already reserved by security principal or security group in Windows operating systems. So, even if you try to create this user account manually in Exchange Server then it will return error
<![CDATA[Active Directory operation failed on domain controllerl. The object 'CN=service,OU=domain.com,OU=Name,OU=Hosting,DC=DCName,DC=local' already exists.]]>
For details please visit following forum posts:
Trouble logging in? Simply enter your email address OR username in order to reset your password.
For faster and more reliable delivery, add firstname.lastname@example.org to your trusted senders list in your email software.