An “SSL Unavailable” pop-up warning means your connection is not secure.
You may see this error message on your admin page when you first set up a custom domain on Shopify. If you recently set up your custom domain, then don’t fret, as it can take up to 48 hours for Shopify to implement an SSL certificate.
If you did not recently initiate a custom domain for your online store, other issues might be at play.
Check Your Domain Records
If you set up your domain several days ago or longer, you may be getting an SSL Unavailable error message because your domain record settings are not configured correctly.
There are a few things to check to see if this is the case. One problem may be that your A (address) record, which points a domain to an IP address, isn’t pointing to Shopify’s IP address. This is common if you’re using a third-party domain provider.
Your Shopify domain can only use one A record. You may have an unavailable error message if your domain has more than one.
You may also unwittingly have Domain Name System Security Extensions (DNSSEC) enabled on your domain. DNSSEC adds an extra layer of protection to a DNS by using public-key cryptography.
While that may sound good, it actually makes it difficult for applications to ascertain if the environment is safe enough to operate in, which can result in applications failing to connect and not working as expected.
If your store uses Certification Authority Authorization (CAA) records, it may require extra certificate authorities to work with your Shopify domain. This is because the purpose of a CAA is to restrict access to Certification Authorities and minimize security threats.
Shopify does not recommend using CAA records, but if you do choose to use them, each must be authorized by CA groups digicert.com, letsencrypt.org, and globalsign.com.
Also, ensure an AAAA (quad A) record is not attached to your domain. These point to IPv6 addresses, unlike A records that point to IPv4 addresses. Different IP addresses can face issues when trying to connect to AAAA record addresses and will fail if they encounter duplicate definitions, which they handle like a security breach.
If you suspect you have domain record issues that need troubleshooting, you must log in to your Shopify admin account, go to Online Store, select Domains, then click DNS Settings. From there, you can check your A records and security extensions and remove any that are unnecessary.