What's changing
Starting September 18, 2018, AdWords API requests that attempt to target or exclude a Placement criterion where the url is exactly adsenseformobileapps.com will fail and result in a CriterionError with reason INVALID_PLACEMENT_URL. You can read more about this change in the Google Ads help center.

What you should do
Modify your application so that it does not add the above Placement criterion via the AdWords API, and review and modify your mobile targeting to achieve your campaign goals. You will no longer be able to exclude all mobile apps from targeting using this Placement criterion, but you can refine your mobile app targeting and exclusions using any of the following criteria:

• Content exclusions
• Device types
• Mobile app categories
• Mobile carriers
• Mobile platforms
• Placements
• Verticals

For more details, check out the criteria usage grid that indicates which criterion types can be targeted and excluded at the campaign or ad group level. If you have any questions or need help, please contact us via the forum.
- Josh Radcliff, AdWords API Team

Source: Google Ads Developer Blog