Missing 50%+ "fbc/fbclid"

I am facing a problem with fbc/fbclid. Google tag manager can’t collect almost 50%+ fbc/fbclid value from cookies or URLs. That’s why Facebook campaigns can’t recognize the sales coming from facebook ads or other traffic sources. The result: if I got 20 sales from facebook ads, Shopify shows the UTM parameter ( that’s why I am 100% sure those sales from FB ads campaign ) , but the Facebook ads manager shows 8-10 sales from facebook ads ( I only run FB ads and it’s my new Shopify website ).

  • Is there any way to capture the fbc/fbclid value from the Server GTM container and send it back to Facebook Conversion API?
  • or how can I improve the tracking?

Thank you.