I have the exact same issue here, on console have the following issue:

Error parsing plugins : Hostname/IP doesn't match certificate's altnames: "Host: packages.nodebb.org. is not in the cert's altnames: DNS:[domain].com, DNS:www.[domain].com"

I have an instance of nodebb running in a subfolder of another site that is served via https. I can view the forum site without any problems but cannot view or install plugins (its possible I cant do other things but this is the obvious problem at this point).

The error I get is the following:

Error parsing plugins : Hostname/IP doesn't match certificate's altnames: "Host: packages.nodebb.org. is not in the cert's altnames: DNS:[domain].com, DNS:www.[domain].com.

How can I overcome this problem?