This is what firefox tells me. Looks OK to me.
Then blush - using exactly https://www.dnssec.co.za gives me a certificate error.
I guess I never type that in.
Wildcards are meant to be coming in the new year - may just live with it.
Even with wildcards, a cert for *.example.com won’t cover example.com so you would still need both if you want both to work in all browsers.