If your SSL certificate expires, it becomes unavailable. You must renew your certificate in a timely manner before it expires, re-bind a domain name to the certificate, and submit materials for review.
After the review process is complete, a new certificate is issued. You must install the new certificate on your server to replace the expired certificate.
Note
You must renew a certificate 3 to 10 business days before the certificate expires so that the new certificate can be issued before the existing certificate expires.
For more information, see Renew an official SSL certificate.