Hello,

I saw the screenshots you attached.

Please make sure that you have added the class to the link you added to open the newsletter.

Screenshot for Clarification: https://prnt.sc/kf6hxn

2. Then navigate to the Theme settings > Shop > Promo popup and add the HTML block ID to the promo pop. Then clear cache and check back.

Screenshot for Clarification: http://prntscr.com/kf7ay5

Regards.
Xtemos Studios.