Google Ad Exchange (AdX) was not detected in your Google Ad Manager (GAM) account. AdX is the premium version of AdSense and the top performing ad network in the world. Your ad revenues are suffering by not integrating AdX into your GAM account.
Step 1: Open your Ad Manager account
Step 2: Go to Admin > Global Settings
Step 3: Check to make sure Ad Exchange is linked
Step 4: Run a Query to find out if there are Ad Exchange line items targeting all of your active ad units.
Step 5: Check your Ad Exchange line item settings. Pay attention to the targeting criteria.
Step 6: Check your Ad Exchange pricing rules. Too high CPM floors could result in a lot of advertisers ineligible to bid on your traffic.