How to generate a free SSL certificate

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To be able to park your custom domain to your Post Affiliate Pro accountit is also required to have an SSL certificate for your custom domain. You can use either a certificate created directly for the specific subdomain, e.g.,, or a top domain wildcard certificate, e.g., *

If you are starting a new business or need to set up a custom domain as soon as possible without paying for an SSL certificate you can also use a free SSL certificateFree certificates are most commonly valid just for a few months. Therefore when your certificate expires you must renew it and insert a new certificate again into Post Affiliate Pro Domain settings. It is not possible to update certificates automatically. We've prepared for you a guide on generating such a free SSL certificate issued by ZeroSSL.

ZeroSSL provides only 3 free SSL certificates valid for 90 days, not lifetime free certificates. It is possible to generate a free certificate only for a specific domain like, not a wildcard certificate like * After you use up all the 3 free certificates, it would be required to pay for any other certificates from ZeroSSL or find another issuer.

Check your domain, and create a ZeroSSL account or log in

Go to the website, write your chosen custom domain, e.g.,, into the top "Create Free SSL Certificate" field, and hit "Next step".

Depending on whether you do or do not have a ZeroSSL account, you will be requested to log in or sign up.

  • If you create a new ZeroSSL account, you will be taken directly to the "New certificate" screen
  • If you log in to an existing ZeroSSL account, you will be taken to the "Certificates" section, from where you can create a new SSL certificate

Generate certificate

There are four mandatory sub-sections in the "New certificate" section: Domains, Validity, CSR & Contact, and Finalize Your Order. To keep the certificate free, you can insert only one specific domain and choose the 90-days validity. In the "CSR & Contact" sub-section, turn off the "Auto-Generate CSR" option and activate the "Paste Existing CSR" option. The needed certificate signing request (CSR) can be downloaded in Post Affiliate Pro Domain settings.

Verify your domain

When you proceed to the next step, you will be asked to verify your domain. There are three available verification methods: Email Verification, DNS (CNAME), and HTTP File Upload. You can choose any of these three. If you are unsure which one will be the best, please discuss it with your server administrator/hosting provider.

Install certificate

After the verification is done, your free SSL certificate will be generated and available to download as a ZIP file. This file will contain all the necessary inputs that need to be inserted into the Post Affiliate Pro Domain settings - certificate and ca bundle. When you complete the custom domain setup in Post Affiliate Pro Domain settings, finalize the SSL certificate installation also in the ZeroSSL panel.