Hi I'm running Version 6.1.0 and was trying to add some extensions for new hires. When I try to create the extension I get the following pop up window: Extension number is in use. Type another one. I know the extension is not is use as I checked in the other drop down list for the DID etc. I've tried different extensions. I've also tried to delete an extension and add it back. I can modify an existing extension but not add a new extension. I'm wondering if my install has become corrupted because I also have another issue where after a reboot the 3CX server it is unable to transfer calls to the exchange server. The only way I have found to fix it is to change the exchange server definition from a hostname to an IP. I have to do this now every time I reboot the server. If I was to do a backup and then reinstall would the issue be transfered over? I don't want to have to rebuild the system from scratch. I've also checked the logs and can't find anything indicating the problem. This system was orignally install as version 5 and then upgraded. Extensions have been added since the upgrade. Any help would be appreciated.