Hey
@david_lfe,
Thanks for providing more info. As
@Saqqara correctly mentioned, I would first recommend that you make sure that an ntp client has been installed on the Debian 9 machine as mentioned in our
3CX/Hyper-V Installation guide and ensure that the guide was generally followed for deploying 3CX. The NTP client is required to avoid timedrift issues on the 3CX Host OS that could potentially cause extensions to unregister and calls to drop along with other various issues.
I would also recommend accessing the Management Console and navigating to
Settings >> Email >> Notifications. Make sure that the "
3CX Services are stopped or fail" notification is enabled so that you have more information regarding which services stopped, if any, the next time the issue occurs.