- Log in the Plesk admin portal, and navigate to Home >> Tools & Settings.
- In the Security group find the SSL/TLS Certificates menu and click it.
- Under List of certificates in server pool section click the Add button
- The Upload the certificate as text section upload the KEY, CRT, and -ca.crt, and click the Upload button.
- In the List of certificates in server pool section check behind the new certificate checkbox, and click the Make Default button
- Next step, go to the Home >> Domains menu, and search the default server domain name, then click the domain name.
- In the summary page find the Hosting Settings link, and click it.
- Under the Security section, select the newly installed certificate, and click the Apply button.