"One or more intermediate certificates in the certificate chain are missing. To resolve this issue, make sure that all of the intermediate certificates are installed" is prompted when a free SSL certificate is deployed on the IIS web server.
Intermediate certificates are missing.
Log in to the SSL Certificate Service console and view the encryption algorithm type of your certificate.
Download the intermediate certificate file to your CVM instance based on the encryption algorithm type of your certificate.
On the target server, double-click the intermediate certificate file and click Install Certificate in the pop-up window.
In the certificate import wizard, set Store Location to Local Machine and click Next.
In Certificate Store, select Place all certificates in the following store > Intermediate Certification Authorities and click Next.
Check the location to install the certificate and click Finish.
If "The import was successful." is displayed, the operation is successful. Then, try deploying your SSL certificate again.