SSL Error for only one website, meanwhile other one is working | ERR_CERT_COMMON_NAME_INVALID

Question

I'm editing two websites for my client. He asked for a HTTPS connection.

While one is working perfectly we have a problem in another one (same IP address, same certificate).

First website throws an error in browser, other one is fine.

I even made a SSL Report by ssllabs.com and I checked the differences, everything should work fine.

Here is a screen from test: DIFFCHECKER SSL COMPARSION

Client get ERR_CERT_COMMON_NAME_INVALID on both Mozilla Firefox and Chrome as in thread name.

I guess something is wrong with website, but i don't get it at all.

Is there anyone who had similar problem or could look at both and tell me where should I search for problems?

Answer 1

Actually I figured this out.

Client was connecting via www.domain.com while I was connecting via domain.com .

SSL wasn't configured by default to support www before the domain name.

Why first website was working for client and second not? Because he connected to first one via www and he didn't while connecting to another one. And browser remembered that choice.

Always check SSL Wildcards fellas!