Outbound calls to problematic numbers ring on all pbx phones

Outbound calls are working normally except the dialed number doesn’t exist or has some issues. In that case insted of getting some announcement (this number doesn’t exist …) all other phones in the office start to ring.

That is pretty certainly ‘Operator Error’, check all you work especially with outbound routing

You mean there is an issue with some parameters that were set during the configuration? By the way I am looking for some paid support for free pbx. Any ideas where to look?