1. Identify the type of error. There are three types of errors that can appear when handling certificates: Your computer does not recognize the certificate, the certificate is out of date (expired), or there is an incorrect URL attached to the certificate. To identify the error, attempt to reproduce it by visiting the site. The error should give some information as to why the validation did not succeed.
2. Click on View Certificates in the address bar (Internet Explorer). If you're using a different browser, select the option that allows you to view your current certificates.

3. Click on Install Certificate (Internet Explorer). On other browsers, select the option that allows you to install or add a certificate to the browser. After you've clicked Install Certificate, click Next.
4. Set the location where the certificate will be stored. This should be determined for you and set to the browser's default location. To finish the installation, click Next. Then click Finish.
5. Confirm the install by clicking Yes. After you've done this, the certificate should be installed. The next time that you visit the site, you should not receive an error.