This means you have an ad size configured for the ad unit but it’s not part of the size map. This mistake could mean bids for this ad size won’t be eligible to serve.
Step 1: Review your ad unit sizes and determine if all sizes are correct in Ad Manager
Step 2: Open your PubGuru header bidding configuration and cross check with the sizeMapping ad sizes and ensure every single one is defined at least once:
Step 3: Update sizeMap if necessary (e.g. missed to add 300×250 on a certain midWidth)
Step 4: If an ad unit will run only on a specific device, still add other devices’ minWidths, but don’t add sizes to it.
A mobile unit will have the following size mapping setup:
A desktop/tablet unit will have the following size mapping setup:
Step 5: Save and publish the configuration