The requirements and process for approving your creatives varies slightly for each exchange.
Microsoft Monetize
To start creative review and approval on Microsoft Monetize, make sure the creative is active and assigned to an active line item that targets inventory from Microsoft Monetize.
Creatives must be manually reviewed before they can serve on Microsoft Monetize. The Microsoft Monetize creative review team also checks that creatives meet Microsoft Monetize's Policy for Buying (external site, requires login).
Microsoft Monetize's review team works 8 AM to 5 PM ET Monday—Friday, and promises a 24-hour turnaround time for creative reviews. Please note this turnaround time can be slightly longer at the beginning of a quarter.
If a creative is rejected by Microsoft Monetize, contact Microsoft Monetize support for help. To contact Microsoft Monetize, please visit https://help.Microsoft Monetize.com/and include your Microsoft Monetize Creative ID.
Google Ad Manager
A creative must meet Google Ad Manager's advertising policies prior to being able to bid on Ad Manager inventory. In addition to Ad Manager's initial review, creatives may be manually reviewed at any time by Ad Manager while they're serving.