Yarn fails to download

The download of Yarn is failing…

SSL: certificate subject name (*.netlify.com) does not match target host name ‘yarnpkg.com

That’s quite an odd error!

Could you please tell us how you are getting it? Please share the entire command you run and all error messages and all other associated log messages and link to a deploy log in case you are trying to run this within a Netlify site build.