To set up Google Bidding in MAX, start by following the instructions for Google setup in our MAX SDK Bidder Network Setup Guide. If you still have difficulty, try the following troubleshooting strategy:
The most common reason that MAX Google Bidding integration doesn’t work is that you need to create a new AdMob Ad Unit specifically for Google Bidding. In other words, you cannot use an existing AdMob Ad Unit.
Your new AdMob Ad Unit must have the Partner bidding box checked, as shown in the image below:
If you followed the complete setup instructions and set up a new AdMob Ad Unit with the Partner bidding box checked, but still cannot get Google Bidding to work in your MAX mediation, open a support ticket at the Developer Support portal.