Go to https://web.sirena.app/manager/profile/groups > click on the three dots located on the right, above the list of users > then click on "General" > "Enable Unassigned list" > and finally press "Accept":
Then log out and log back in to save the changes.
What’s the difference between the classic Unassigned view and the Unassigned list?
If the Unassigned list is on, you’ll be able to see a list with all the clients waiting to be served:
On the other hand, if the Unassigned list is off, it’s not possible to choose which client will be served first. The agent will only be able to see one client at a time, sorted by date from the oldest to the newest:
Note: If the user is "Not Available" the Unassigned list will not be activated. The alternative would be to set it to "Available" and configure your service hours as "closed" every day, so you can see the list and no new contacts will be entered.