Cal here from Shopify, thanks for reaching out to us. Are you having trouble connecting a domain to your connect? Who is your domain host? What is the domain?
Have you added the correct A and CNAME record to your DNS settings:
Your A record should point to Shopify's IP address, which is
www CNAME record should point to
Please bear in mind, there should be no other A records in your domains DNS dashboard. We have the full guide here if you want to go through it step-by-step. Let me know how it goes!
I suggest contacting your domain host support directly, who will be able to assist with inputting the correct DNS settings for Shopify. Once those records are updated, adding the domain to your store will be very straight forward. Let us know if there's anything we can do from our end.