Check three things: you have access to an assigned list, the list has a call number, and your browser has access to the microphone.
You cannot start a second session while a call is already in progress.
Open the Dialer from the main navigation.
Select the list to call in the header.
Check the progress section shown for this list.
Click Start.

Ubic places calls based on the list settings. If no one answers or the line is busy, the lead becomes Frozen and the Dialer moves to the next attempt.
As soon as a lead answers, the call window opens with their profile and recent context. In parallel dialer mode, Ubic stops the other calls still in progress. Those leads also become Frozen because no conversation took place with them.
The progress section separates completed leads from those still to call.
If an automation is active on the list, some leads may be temporarily frozen. They are not included in the session until Ubic returns them to the list to call.
An active session prevents a new one from starting until the current call has ended.
If the list was recently updated in your CRM, you can also reload it from the Dialer before trying again.
CSV lists can be exported from the Dialer.