Gpdr requires the use of double opt-in. Confirming the subscription to the newsletter or mailing list. (e-mail with a confirmation link.)
1. opt-in to checkbox on the website (This is on the checkaout page )
  1. Missing opt-in - link in the email, confirming that you want to subscribe the mailing list.
Gpdr requires use of Two checkboxes -
one for marketing information ( Information not related to the store's offer, )
and other for sending commercial information. ( Related to the store's offer, promotions, discounts, sales, etc ..) - example, I have permission only for commercial information, I can't send marketing mailings.