I Have this same issue. I have been back and forth with Shopify and Facebook for 2 weeks. No one is giving me any helpful information. I made a new business manager, I made a new ad account, etc, but every single thing I try to do is full of error messages. I feel like it should be more simple- but I’m exhausted with all the different support people giving me different views and blaming FB/Shopify. If there is a kind soul out there who had this problem and figured it out, please please reply and give me instructions. I’m lost and I need you!! Thanks.