Depending on your settings, you should also be seeing traffic icons on the moving map itself, showing traffic relative to your position. They will be small elongated triangles pointing in their direction of travel, like arrowheads.
To check your settings, go to Menu > Setup > Alerts and Warnings > Traffic Alerts. From there, set "Distance Visibility" to "Unlimited" and "Vertical Clearance Visibility" to "Unlimited". This should ensure that no traffic targets get filtered/hidden on your display.
Once you have an idea of what traffic should look like on your map, then in congested airspace you may want to change those settings to something more restrictive so that the display is not cluttered with targets that are no threat to you.
There are other settings in that menu area that control how aggressively you are alerted to traffic.