The current Google Ad Manager (DfP) implementation for responsive leaderboard ads may be causing your ads no not appear. What is happening is that the browser tells GAM how big its window is, and GAM sends the creative that corresponds with that screen size. There are 3 sizes (breakpoints) Desktop, Small Desktop/Tablet, and Mobile and there are 3 corresponding sizes for the creative.
Therefore, when setting up a leaderboard ad, you need to provide 3 sizes of creative which are:
- 320x50 or 300x50
If you are missing the biggest size creative, the following how-to will show you how you can set up a 728x90 ad unit to load on the bigger Desktop breakpoint.
1. Under Delivery, go into one of the orders.
2. Look at the creatives.
3. This is the Preview of the creative. Click on the Settings tab to look for the size override.
4. Click on the override checkbox, then click into the field and select the sizes you want the creative to load into.