Common Reasons For Low Clear Rate

As a DSP participating in the MoPub Marketplace, you may find that you are winning auctions, but not successfully clearing (showing) an impression for certain creatives. There can be various reasons for this. Below is a list of reasons for why this may happen. 

Note: This is not an all-encompassing list. We recommend always Self-Testing your creative to ensure everything is working as intended.

VAST

  • Blank XML - Be sure that you are not using a wrapper which points to blank XML.

  • XML errors (i.e. - not properly following the VAST spec).

  • Video file size exceedingly large - We recommend 2MB with a maximum file size of 5MB.

  • Geos with slower internet connection - You may want to consider targeting devices on Wifi only for some countries.

  • Publisher integration - If you notice a high volume of your auctions are being won but not cleared by a specific Publishing App, that could be the driving force behind a low clear rate.

  • Android Volley - Any http -> https (or vice versa) redirect may fail on Android, resulting in trackers not firing or content not loading. It’s recommended that you use the https:// protocol consistently whenever possible.

  • Improper encoding - Any field not properly encoded can result in the impression not clearing. For example, are you using a macro for the Publisher name? Be sure to encode the name to accomodate for any spaces or unexpected characters.

MRAID

  • Ensure you properly declare MRAID - Be sure you are passing MRAID in the crtype field of the Bid Response, as well as declaring <script src="mraid.js"></script> in your ad markup.

  • Verify the Auction supports MRAID - Not all auctions support MRAID. You can avoid targeting inventory that does not support MRAID by looking at the Object: banner.api field in the Bid Request. More information here.

  • Geos with slower internet connection - You may want to consider targeting devices on Wifi only for some countries.

  • Publisher integration - If you notice a high volume of your auctions are being won but not cleared by a specific Publishing App, that could be the driving force behind a low clear rate.

  • Targeting older devices/OS - Certain MRAID ads (especially Playables) can be resource constraining. Older device/OS combinations may have trouble rendering your assets in a timely manner.

  • Do not use document.write - The document.write method has multiple limitations on Android. We advise that you use an alternative function. Below are two known limitations:

    • The document.write function is blocked on Android for users on slow connections such as 2G. More information on Google’s Chrome Status page here.

    • The document.write function does not work on Android OS 7.x

Native

  • Assets are unaccessible - Ensure that the assets you are linking to (Main Image, Icon, etc) are accessible.

  • Ensure you are not redirecting to another protocol - Android does not support image redirects to another protocol. Ex: HTTP to HTTPS or vice versa will not work.

  • Publisher integration - If you notice a high volume of your auctions are being won but not cleared by a specific Publishing App, that could be the driving force behind a low clear rate.

  • Android Volley - Any http -> https (or vice versa) redirect may fail on Android, resulting in trackers not firing or content not loading. It’s recommended that you use the https:// protocol consistently whenever possible.

  • ATS - Some Publishers may enable ATS, meaning DSPs must use secure links (https) for the following fields in the Bid Response:
    • native.assets.img.url (id 2)
    • native.assets.img.url (id 3)
    • native.assets.imptrackers[] (array)
    • native.assets.video.vasttag (id 7)
  • Native asset sizes
    • Main Image - the minimum size is 800×417 (1200x627, 1200x628 and 800x418 recommended) pixels or greater (with a 1.91:1 ratio) (recommended file size < 100KB for phones, and < 150KB for tablets). Native Main Image sizes larger than 1200x627 can be displayed on Android (all SDK versions) & iOS SDK 4.12 and above.
    • Icon Image - 80 × 80 pixels or greater (with the same ratio) (recommended file size < 15KB)

Last updated October 10, 2018

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