WebCheck validates the certificate during an HTTPS request. If the hostname, trust chain or TLS connection cannot be verified, it records a TLS error instead of treating the endpoint as healthy.
The certificate does not match the hostname
Check the certificate’s Subject Alternative Names and confirm that the certificate served by your load balancer or proxy covers the exact hostname in the WebCheck target.
The certificate chain is not trusted
The server may be missing an intermediate certificate, or the chain may not lead to a trusted issuer. Check the certificate bundle installed at the TLS terminator and test the public endpoint after updating it.
The TLS connection cannot be negotiated
A protocol error can point to incompatible TLS versions or ciphers, or a proxy that is not serving TLS correctly. Fix the endpoint configuration; do not turn off certificate verification to silence the warning. WebCheck also reports expiry details and warns when a certificate is within its configured warning window.