Here are the steps you can follow to setup/update COMODO SSL certificate in a Nginx server setup using easyengine.

1. After you buy the certificate you will receive a zip file and a key file in the format of domain.name.key and domain_name.zip. Extract the zip file, it will have following files
   1. AddTrustExternalCARoot.crt
   2. COMODORSAAddTrustCA.crt
   3. COMODORSADomainValidationSecureServerCA.crt
   4. yourdomain.com.crt
2. You need to make a bundle of these files into one crt file.
3. To do that open yourdomain.com.crt file in a notepad and save as 'bundle.crt'
4. Then open each of the files, copy everything in them and append it to the bundle.crt file.
5. Now create a 'cert' in your  /var/www/yourdomain.com/ directory on the server.
6. Move both yourdomain.key and bundle.crt file to cert folder.
7. Edit ssl.conf file in /var/www/yourdomain.com/conf/nginx/ directory.

listen 443 ssl http2;
ssl on;
ssl_certificate     /var/www/yourdomain.com/cert/bundle.crt;
ssl_certificate_key     /var/www/yourdomain.com/cert/yourdomain.com.key;

8. Now restart Nginx and you are done.

   service nginx restart

    

To validate if everything is setup properly you can go to https://comodosslstore.com/ssltools/ssl-checker.php and put your domain name and check. In case you make any mistake make sure you have followed step 2, 3 and 4 properly.

You may receive java.security.cert.CertPathValidatorException when setting SSL certificate, it only means that your Intermediate/Chain certificate is missing, again the solution to this is to make sure you have followed step 2, 3 and 4 properly.