Facebook Pixel Not Firing


Apologies if this is a silly question:

I have created a free mini course page https://breastfeeding.thethompsonmethod.com/free-mini-course/

The Opt-in form is a pop-up lightbox, once the form is submitted it takes them to a thank you page https://breastfeeding.thethompsonmethod.com/thank-you/

I am running FB ads to this opt-in page. In order for me to track lead conversions in FB ads manager, I thought I needed to create a custom conversion where the rule is URL Equals breastfeeding.thethompsonmethod.com/thank-you/

I then added this little bit of script to my facebook base pixel fbq(‘track’, ‘lead’); and placed that in my unbound scripts under my thank-you page.

I am running my ads and have since had 22 leads appear in my unbounce account, but FB ads is showing 0 leads. What am I missing?

Thanks in advance.