Installing Certificate SSL

Installing SSL Certificates from Comodo / InstantSSL.com on Plesk Hosting Servers

Setting up an SSL certificate in Plesk is not for the faint of heart. And if you're looking for solutions online, there are few places that will provide you with the information you need. However, before paying anyone to install your SSL certificate, please follow the instructions detailed here. And, if you're still having problems, then pay for help. This solution is platform-independent, so any Plesk server may be able to benefit from the following information.

After I purchased my "EssentialSSL" SSL certificate from Comodo I specified that the CSR was created on a Plesk server. After payment was made, I was emailed the following files:

AddTrustExternalCARoot.crt ComodoUTNServerCA.crt EssentialSSLCA.crt mysecuredomain_com.crt UTNAddTrustServerCA.crt

I returned to the certificates section in the Plesk control panel and selected the domain (mysecuredomain.com) for which the certificate was created. I copied and pasted the mysecuredomain_com.crt into the Certificate box, and I copied the EssentialSSLCA.crt into the CA certificate box. This part to me seemed like common sense. That is until I got the message 'The CA certificate does not sign the certificate'.

No matter what I tried, when uploading the CA Certificate, Plesk would give this warning.

As it turns out, you actually need ALL FOUR of the CA certificates appended together in a particular order so as to successfully install the certificate into Plesk.

You should first copy and paste the 'mysecuredomain_com.crt' certificate into the Certificate box.

Then you should copy and paste IN THE EXACT ORDER BELOW, the following certificates, with NO BLANK LINES in between:

EssentialSSLCA.crt ComodoUTNServerCA.crt UTNAddTrustServerCA.crt AddTrustExternalCARoot.crt

Those files should have been emailed to you upon purchase. At this point, click the 'Send File' button and assuming your domain has an Exclusive IP address assigned, the certificate should be installed successfully.

The order you place the contents of those files into a new file is important, and should be followed as outlined above. No blank lines should be added between the certificate contents when you copy the contents of the four existing CA certs into a new file.

Good luck.