So...the year is up and the SSL cert was renewed. Installed it exactly like I did last time.
...and now the other store doesn't work "Could not be Reached" unless I uncheck the SSL in Nop for that store.
Main store still works fine.
According to: https://www.sslshopper.com/ssl-checker.html#hostname=sstubes.com
the SANS has the second store in it.
I have no idea what to do now...This should freaking work. It worked last time.