Pixel events fail in FB in-app browser but work everywhere else

1

Let me explain my issue clearly.

I run an E-commerce website:

  1. Domain: Bought from Namecheap

  2. Hosting: DigitalOcean (through Cloudflare)

  3. Platform: WordPress + WooCommerce

Active plugins include:

  1. CartFlows

  2. Elementor + Elementor Pro

  3. GTM4WP (Google Tag Manager for WordPress)

  4. WooCommerce + WooCommerce Direct Checkout

  5. Filter Everything (WooCommerce filter)

  6. WP Rocket, WP File Manager, WP Rollback, WPCode Lite

  7. WPvivid Backup Plugin, All-in-One WP Migration (+ Unlimited Extension)

Tracking Setup:

  1. Created a Meta Pixel in Business Manager.

  2. Connected the pixel to my site using GTM4WP.

  3. Set up tags and triggers in Google Tag Manager (PageView, ViewContent, AddToCart, InitiateCheckout, Purchase, etc.).

  4. Using two GTM containers → Browser + Server.

  5. Configured Conversion API via Facebook tag templates.

  6. For server-side tracking, I used Stape.io with a custom subdomain + CDN.

Everything is connected properly.

The Problem:

When I test in Event Manager (Test Events tab):

  1. On desktop browsers → all tags fire correctly.

  2. On mobile browsers (Chrome, Safari, etc.) → all tags fire correctly.

  3. On Facebook in-app browser (inside FB app) →

    -Sometimes ViewContent doesn’t fire.

    -InitiateCheckout never fires.

This only happens with the Facebook in-app browser.

Question:

  1. Why does this happen specifically in FB’s in-app browser?
  2. And what’s the proper fix so that InitiateCheckout (and other events) fire reliably there as well?
2

Hi @Md_Jahid_Hossain,

  1. Which tags don’t fire? The ones from sGTM? Or the ones from web GTM?
  2. What is the tag that you’re using to ingest data into sGTM? GA4? Data Tag?