This uses LetsEncrypt which doesn't support wildcard certificates yet:
> Will Let’s Encrypt issue wildcard certificates?
> We currently have no plans to do so, but it is a possibility in the future. Hopefully wildcards aren’t necessary for the vast majority of our potential subscribers because it should be easy to get and manage certificates for all subdomains.
> Will Let’s Encrypt issue wildcard certificates?
> We currently have no plans to do so, but it is a possibility in the future. Hopefully wildcards aren’t necessary for the vast majority of our potential subscribers because it should be easy to get and manage certificates for all subdomains.
From https://community.letsencrypt.org/t/frequently-asked-questio...