<p><strong>You may use only one of this fields:</strong></p>
<ul>
    <li>Guid</li>
    <li>Username</li>
    <li>Email</li>
    <li>Identifier</li>
</ul>
<p>The field 'Identifier' may contain a Guid, Username or Email. Use this field only, if you don't know, if you have a
    Guid, Username or Email. It may be slower than to select the type.</p>