Hi Andirose,  I think this is now solved.  I went to this page https://help.shopify.com/en/manual/domains/managing-domains/edit-dns-settings and then entered the live chat to speak to a shopify advisor.  after sending screenshots of teh error message...

Hi, I send email campaigns with Mailerlite and have to authenticate my sender email domain  in order to better send the campaigns to my email subscribers.  I have added the DNS records to the domain section in Shopify but when I try to check the DNS ...

Hi, this is a thread from a couple of years ago but I'm having the same issue.  However, I cannot see a way to separate the subdomains from the main domain when adding to the allow list.  See screenshot below.  I wonder if anyone else is having this ...