Facebook conversion API deduplication, worked once

Hello everyone,

As the title suggests, the deduplication process works sometimes, but mostly not. I noticed a strange behavior on my Facebook test environment. Even though I managed to create and pass same event ids for sGTM and pixel the output is not how it’s supposed to be.

To be exact the events coming from Server and Web are not grouped even though they have the same ids

You can see more details on my screenshots bellow:


this is the only time that worked:


Make sure to add your domains to traffic permissions in Pixel settings, recently we’ve seen the behaviour you’re describing and it was fixed by just that.

Thanks for the quick reply.

I already did that step some days ago:

I have completed the step you suggested and unfortunately i am still getting the same results. Could it be something else? Thank you for your time and assistance.

Hi Jit,

In spirit of customer support I can suggest you try removing all domains and add them again :slight_smile:

In my practice I have only seen this caused by traffic permissions. I suggest you try bringing this up to your/customer’s FB rep. Perhaps they can shed some light on it.


  1. Please make sure the Facebook Pixel event has the same trigger type with the respective GA4 event. If you put Facebook pixel PageView trigger type is DOM ready, GA4 PageView must be DOM ready.

  2. Try to open GTM web container preview mode on the same chrome profile where you open Facebook event manager to address the grouping issue. It works for me.

By the way, template gallery has an Event ID variable (by mbaersch) that works for evey events.

Hope it helps