1. Go to http://cp1.nextiva.com
Login using the credentials Nextiva gave you for your group admin login and password.
2. Click “Users”
3. Without selecting anything else, click on “Search”
4. Select the user whose extension you are looking for.
5. Select “Addresses”.
6. Find the user’s extensions as shown below.
You will usually have 2. One will be @nextiva.com and the other will be @prod.voipdnsservers.com