Microsoft Invest - Dynamic landing pages
As an advertiser, you may wish to send users to different landing pages or compare the performance of different landing pages. To accomplish this, you can associate a landing page URL with a line item. This landing page will then be available for association with any creatives that are attached to that line item.
You can still attach a landing page URL at the creative level. However, if you select the Set a landing page at the line item level radio button on the Create New screen, you will only be able to associate the landing page URL at that level. If the Set a landing page at the line item level radio button is selected and there is no landing page URL at the line item level, the creative will not serve.
Note
All landing page URLs must have https:// included in the URL string. For example, https://www.appnexus.com is a valid landing page URL. Excluding https:// from the URL string may result in errors.