We have 3CX running quite happily - for security, we have disabled outbound calls to most international destinations. In reviewing event logs, we see last night the following entry: Call from  to  has been rejected by the 3CX Country Blocking Feature . Reason: 00442033477788 contains Prefix 0044. Calls to 0044 are not allowed by system. Resolution: To allow this call access the 3CX Management Console, Settings, Security, Allowed Country Codes and enable the country or continent that matches this prefix. Prior to this we see an error a few minutes earlier: Device 442033477788 dialed on (AnyLine@<provider>) had no available outgoing trunk(s) for Call(from "442033477788--12098130127"<sip:888@<our IP address>;tag=063b285b to 442033477788) Please note - in above, <provider> is the name of our VoIP provider, and <our IP address> is our public IP address. We don't use such an extension, and nor have we set up/configured fax (from what I read, extension 888 has to do with faxes). The above looks to me like a hacker managed to log in to extension 888, and try to send a fax? I have looked all over the management console, and I can find nowhere to change the password of this extension? Could I trouble if anyone has an insight into the above to share with us please?