When did you configure the domain? SSL might take some time to be available, so don't worry if it shows unavailable now:
When you add your custom domain, a new SSL certificate is automatically created. This process can take up to 48 hours. During that time, you might see an error that reads SSL Unavailable in your Shopify admin and you might see a security error in your browser when you visit your online store. Learn more about the SSL Unavailable error and steps you can follow to troubleshoot it.
Please share your url and screenshot of error here.
Nick here from Shopify.
As @gseilei touched on, sometimes this can just take some time. After a certain time period, it will change from Unavailable to Connected and it will act as is supposed to. The documentation @gseilei shared has all the information you need for this.
If this is still not working for you after 48 hrs can you let me know in a reply here and I can take a closer look for you.
All the best, Nick
I'm not 100% sure what you're referring to. When you say:
I checked it’s under a third party domain but I purchased domain by Shopify they also say my A records but I have no option to edit
do you mean you purchased the domain from Shopify or a third party domain provider such as godaddy?
Could you also share a URL to your store with the domains and subdomains you are using and I can test it out and see if they are working on my end?