I just noticed today that when you sign up using the ninja form, it no longer signs the affiliate up, or creates the coupon.
It does, however: Create a WP User, Sends the notification created in affiliates pro, and the other actions on the ninja form.
I have this on two sites and it WAS working on both sites, but now does not work on either site. The regular affiliate form works ok, but I require you to be logged in to use that version, as it does not sign you in automatically. The Ninja form is being used to create the new account along with signing them in and redirecting them to the coupon code page.
I did notice that WP updated both sites to 5.4 yesterday. Can you help me figure out why the registration does not work? I turned on wp_debug and have not found anything helpful there.