Vitalpbx communicator double call

Hi
I got a issue with the Vitalpbx communicator on computer
When they receive a double line they lost the audio on the first call when the second call is transfert to mailbox and never came back so we need to hang up and recall
Did you have any idea of how I can fix that
Thank you

Vitalpbx Communcator is depricated …
Use vitxi or microsip