I have some user data parameters from Facebook's Marketing API (https://developers.facebook.com/docs/marketing-api/server-side-api/parameters/user-data#external-id) that I wish to send using Pixel (fbq function)
Let's take one of the user data parameter - external_id I am currently doing something like this -
fbq('track', 'AddToCart', {external_id: 1234})
The documentation on the aforementioned url states that you can send these values using fbq('init') function, but I wasn't sure if its applicable with fbq('track') function too.
On another note, recently I got this mail from facebook that "Your server is sending the external_id parameter for your AddToCart event inside the custom_data field section of your payload. External_id is invalid unless it is sent as user data field"
What could be the reason for it? the documentation states you don't need to wrap external_id inside user_data field if sending through pixel. Is this issue message incorrect?
