FritzBox 7390 Configuration Before you begin, ensure that you've created your extension in the My Account Portal, https://my.maxo.com.au/. To retrieve the details of an existing extension, or create a new extension, login to the My Account Portal and select SIP Trunks from the menu. If you're creating a new extension, click the Add Extension button, fill in the details and click Save. For additional information on creating an extension, please see Portal Guide - PBX Extensions and Sip TrunksFind the extension number you're configuring, then click Edit.