What is the "Server Sending Invalid Match Key Parameters" alert?

After enabling the Conversions API, if you see this kind of warning in your Business Manager:

This is due to the use by some of your customers of a cookie blocker like "adblock". Some data (IP, state, city name, etc...) are then incorrectly formatted according to Facebook guidelines. These are only warnings and can be ignored.

However, if you don't want to see these warnings anymore, you can stop sending the data that is causing problems by updating your module to version 1.4.0 and activating the "No longer see warnings due to cookie blockers" option in the module. To do this, go to the "Facebook Pixel" tab of the module and to the "Pixel code" sub-tab: