When connecting VPN from FortiClient getting the error message

[priyarf5]

Hi,

When connecting VPN from FortiClient getting the error message “The security certificate for this site has been revoked. This site should not be trusted”.

I have verified the server certificate used under SSL-VPN settings and found that certificate is valid.

FortiOS version - 7.0.15

[ozkanaltas]

Hello @priyarf5 ,

The certificate may be valid but may have been revoked by a trusted authority.

Can you try to test with this tool your certificate? 

https://www.ssllabs.com/ssltest/

[JNDias]

If you are using public certificates, another reason can be because the certificate is revoked at the CA level when the certificate uses ocsp.

You may check with the following tool: https://www.certificatetools.com/ocsp-checker

Example:

Full KB: Troubleshooting Tip: FortiClient error certificate for this site has been revoked