For troubleshooting SSL issues, we have the an SSL Checker: It will analyse your SSL configuration in Apache. It will show which certificate file is being used, the domain name it has, whether the key and certificate match and will also check the server certificate. Execute these commands inside your instance (connect through SSH).
chmod +x ssl-checker-v1.0.0-linux-amd64
./ssl-checker-v1.0.0-linux-amd64 -hostname PUT_YOUR_DOMAIN_NAME_HERE
Please show us the results of executing the command.