Too Many Ad Units Defined for Header Bidding. Here’s How To Fix It.

We generally do not recommend more than 5 ad units per page unless extremely necessary (e.g. lengthy content).


Step 1: Audit your Header Bidding configuration to make sure Device is properly set per ad unit:

mobile ad unit

Step 2: If you have an OFF-page + responsive setup, when adding the ad unit twice, Device needs to be specified for each and corresponding Placement ID/parameter added:

ad unit code for mobile

ad unit code

Step 3: If you have an ON-page setup, check that Device detection codes are set to properly load the ads based on device

Device detection codes


  1. It is important that you have no more ads on your site than visible content.
  2. Google’s policy no longer restricts publishers in terms of the maximum number of ads per page but recommends that there should be as much original content as ads. Find more information here:
  3. Less is more. When you have too many ads on the page, they tend to negatively impact one another, stealing attention or clicks from one another and they all end up losing.
  4. Advertiser bids tend to be lower when there are too many ads. Consider this: why would a buyer pay a $5 CPM for an impression above the fold, when there’s another ad below the fold that he can win only at $2.50?
  5. Less ad slots available could mean tighter competition. Advertisers will put their best bids forward to win.

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