What does Invalid Server Certificate mean?

An "Invalid Server Certificate" error occurs when a web browser or application cannot verify the authenticity of a server's SSL/TLS certificate. This can happen for several reasons, such as the certificate being expired, self-signed, or not issued by a trusted certificate authority (CA). It may also indicate potential security risks, such as man-in-the-middle attacks. To resolve this issue, the server's certificate needs to be updated or properly configured.