Secure more than one instance - localhost (no replies)

I have set up a working certificate for "localhost" on Wamp Server 3.0.8 32bit on my windows 10 PC. I thought/hoped that would work, be inherited, for my other project as well, "mb219dev", which I use as a Joomla development environment for my live site.

If I try "[mb219dev&quot]; it get this "invalid certificate"/"certificate error" or when I try to login "[mb219dev]; it gives "Not Found. The requested URL /administrator/index.php was not found on this server."

Should I now:
1. create a new certificate for "mb219dev", replacing any references to "localhost" (or "www.wamphelpers.dev" as in the tutorial [forum.wampserver.com])
2. or follow the links "to secure more than one site per appache instance" given in the tutorial above?
3. or do I need to look for the error somewhere else?

If alternative 2, I haven't stumbled upon any "ssl on localhost"-tutorial which involves "SSLCertificateChainFile"...

Best Regards
Håkan
Stockholm, Sweden