Pop-up Coupon not working consistently

Hey there,
Since purchasing the license key for this plugin, I’ve noticed a significant decrease in email subscriptions. I used to get 15 – 20 per day, and now I got 1 every few days. I do have people going to the website (as noted by the Facebook Pixel as well as Analytics) but no sign-ups.

I tried using different browsers in different machines to see if the pop-up would appear, and it’s very inconsistent. I made sure in all instances to allow for pop-ups as as well cleared cache multiple times.

Any idea why this could be happening?