Subdomain for Store & SSL Certs

[MtnViewMark]

I have an existing online presence with my own domain name - example.com. I has a web server, has SSL certs, e-mail... etc...

I followed the instructions in the Square help article Use a Custom Subdomain with Your Online Store to set up my shop at shop.example.com.   I made the DNS changes, which went live in seconds - and indeed, I can use that domain name to reach my shop.... but...

The SSL cert at the show don't name my subdomain. It names *.weebly.site (and similar). Because of this, visitors correctly get a giant warning from browsers that the connection to the site is not secure. Clearly, I can't go live with the store like that.

Is a subdomain actually supported in some form? The more I think about it, I'm thinking that it can't be: How can Square/Weebly get a certificate naming shop.example.com since I control example.com.  I'd be happy to generate a proper certificate (since I know the IP address) and send it in... but I don't see any option for doing so.

Is this fixable? Or do I have to give up on the idea of having a subdomain here?

[MtnViewMark]

I'm going to answer my own question: Just wait!

The system will eventually generate a cert for the subdomain and that web server and install it... and it will come up good.

Takes longer than I'd like, and they don't explain that when they tell you it can take up to 48 hours, they mean the SSL cert - because the domain name worked as soon as I changed DNS.