For the CPM model to function properly, you should first set it up correctly:
Mark the checkbox “Track impressions" in the traffic source settings. Shown on the screenshot.
Choose your traffic source in Campaign Settings.
Scroll down to the screen on the first step of setting up a campaign.
Copy the link for impression pixel.
Go to the Tracking pixel section and choose the appropriate pixel.
Replace the link in this section with the pixel display link.
Place the pixel displays into your advertisement.
A pixel will light up every time your advertisement is displayed. Based on this data, we are able to calculate the cost. Some traffic sources, however, do not support this feature. Before using this feature, it is advised to get in contact with a representative of your traffic source.