SSL self signed certificate CER exception added to Keychain but fails in Chrome

Question

Operating System: Mac OSX El Capitan 10.11.5

When browsing to the page I have a Privacy error, although an exception was added.

I have the correct CER file so I added it to my Keychain

TRUST THE CERT on Mac System Keychain

In CHROME Version 51.0.2704.106 (64-bit), still getting an ERROR

THE MESSAGE IN CHROME: [FILTERED].com normally uses encryption to protect your information. When Google Chrome tried to connect to [FILTERED].com this time, the website sent back unusual and incorrect credentials. This may happen when an attacker is trying to pretend to be [FILTERED].com, or a Wi-Fi sign-in screen has interrupted the connection. Your information is still secure because Google Chrome stopped the connection before any data was exchanged.

You cannot visit [FILTERED].com right now because the website sent scrambled credentials that Google Chrome cannot process. Network errors and attacks are usually temporary, so this page will probably work later.

In the URL bar, HTTPS red cross on the lock although "The is certificate is Valid" and marked as Trusted.

In the Security Overview Console, "This page is insecure". Any further pointers?

The self signed certificate should be fine, a friend got it working on a Windows environment. So I may be doing it wrong on my Mac, although, I am pretty sure I've done the necessary.

I have also tried on Firefox and still I get the error.

Any further pointers?

UPDATE 1

openssl s_client -connect mywebsite.com:443

CONNECTED(00000003)
depth=1 /CN=Root Certificate/C=US/ST=California/L=San Jose/O=MyCompany/OU=Self Signed
verify error:num=19:self signed certificate in certificate chain
verify return:0
---
Certificate chain
 0 s:/CN=*.mycompany-labs.com/C=US/ST=California/L=San Jose/O=MyCompany/OU=On Demand
   i:/CN=Root Certificate/C=US/ST=California/L=San Jose/O=MyCompany/OU=Self Signed
 1 s:/CN=Root Certificate/C=US/ST=California/L=San Jose/O=MyCompany/OU=Self Signed
   i:/CN=Root Certificate/C=US/ST=California/L=San Jose/O=MyCompany/OU=Self Signed
---
Server certificate
-----BEGIN CERTIFICATE-----
[FILTERED]
-----END CERTIFICATE-----
subject=/CN=*.MyCompany-labs.com/C=US/ST=California/L=San Jose/O=MyCompany/OU=On Demand
issuer=/CN=Root Certificate/C=US/ST=California/L=San Jose/O=MyCompany/OU=Self Signed
---
No client certificate CA names sent
---
SSL handshake has read 2072 bytes and written 456 bytes
---
New, TLSv1/SSLv3, Cipher is AES256-SHA
Server public key is 2048 bit
Secure Renegotiation IS supported
Compression: NONE
Expansion: NONE
SSL-Session:
    Protocol  : TLSv1
    Cipher    : AES256-SHA
    Session-ID: [FILTERED]
    Session-ID-ctx: 
    Master-Key: [FILTERED]
    Key-Arg   : None
    Start Time: 1468885016
    Timeout   : 300 (sec)
    Verify return code: 19 (self signed certificate in certificate chain)
---
[HANGS]

and with -ssl3

openssl s_client -connect mywebsite.com:443 -ssl3

CONNECTED(00000003)
21775:error:14094410:SSL routines:SSL3_READ_BYTES:sslv3 alert handshake failure:/BuildRoot/Library/Caches/com.apple.xbs/Sources/OpenSSL098/OpenSSL098-59.40.2/src/ssl/s3_pkt.c:1145:SSL alert number 40
21775:error:1409E0E5:SSL routines:SSL3_WRITE_BYTES:ssl handshake failure:/BuildRoot/Library/Caches/com.apple.xbs/Sources/OpenSSL098/OpenSSL098-59.40.2/src/ssl/s3_pkt.c:566:

and

$ nmap --script ssl-enum-ciphers -p 443 mywebsite.com

Starting Nmap 6.46 ( http://nmap.org ) at 2016-07-19 10:27 CEST
Nmap scan report for mywebsite.com (10.234.104.241)
Host is up (0.11s latency).
PORT    STATE SERVICE
443/tcp open  https
| ssl-enum-ciphers: 
|   SSLv3: No supported ciphers found
|   TLSv1.0: 
|     ciphers: 
|       TLS_ECDHE_RSA_WITH_3DES_EDE_CBC_SHA - strong
|       TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA - strong
|       TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA - strong
|       TLS_RSA_WITH_3DES_EDE_CBC_SHA - strong
|       TLS_RSA_WITH_AES_128_CBC_SHA - strong
|       TLS_RSA_WITH_AES_256_CBC_SHA - strong
|     compressors: 
|       NULL
|   TLSv1.1: 
|     ciphers: 
|       TLS_ECDHE_RSA_WITH_3DES_EDE_CBC_SHA - strong
|       TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA - strong
|       TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA - strong
|       TLS_RSA_WITH_3DES_EDE_CBC_SHA - strong
|       TLS_RSA_WITH_AES_128_CBC_SHA - strong
|       TLS_RSA_WITH_AES_256_CBC_SHA - strong
|     compressors: 
|       NULL
|   TLSv1.2: 
|     ciphers: 
|       TLS_ECDHE_RSA_WITH_3DES_EDE_CBC_SHA - strong
|       TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA - strong
|       TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256 - strong
|       TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256 - strong
|       TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA - strong
|       TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA384 - strong
|       TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 - strong
|       TLS_RSA_WITH_3DES_EDE_CBC_SHA - strong
|       TLS_RSA_WITH_AES_128_CBC_SHA - strong
|       TLS_RSA_WITH_AES_128_CBC_SHA256 - strong
|       TLS_RSA_WITH_AES_128_GCM_SHA256 - strong
|       TLS_RSA_WITH_AES_256_CBC_SHA - strong
|       TLS_RSA_WITH_AES_256_CBC_SHA256 - strong
|       TLS_RSA_WITH_AES_256_GCM_SHA384 - strong
|     compressors: 
|       NULL
|_  least strength: strong

Nmap done: 1 IP address (1 host up) scanned in 5.96 seconds