Strangely enough, I got SSL error when I want to access site via netlify url: https://www.team-beta.–mytaple.netlify.app/ and https://www.team-beta.mytaple.netlify.app/
For the domain mytaple.com, team-beta is a subdomain (as is www in www.mytaple.com) so in the domain www.team-beta.mytaple.com the www is subdomain of team-beta which is in turn a subdomain of mytaple.com.
While is it not impossible for Netlify to extend a SSL certificate to cover other subdomains, generally speak having a www subdomain on a subdomain is not (in my experience) standard practice (take for instance these forums which are answers.netlify.com which are not accessible via www.answers.netlify.com.)
This is understandable in part for the reasons outlined above, plus you can’t set up multiple subdomain levels on netlify.app because it is not a domain you control.
Since I had to make it work with www subdomain of the team-beta (that URL was embedded in QR code) I resolved my issue by creating another project pointing to the same repository on subdomain team-beta.mytaple.com and then creating branch deploy on branch called www
