NetScaler is communicating with the OCSP server.
OCSP server is replying for the request by NetScaler, however NetScaler is unable to send the reply of certificate status to the user.
To resolve this issue, upgrade to NetScaler 11.1 < Latest Version > and also add configuration as below:
add ssl ocspresponder o1 –url <OCSPResponderURL> -nonce DISABLED
bind ssl certkey <certkey_name> -ocspresponder <ocspresponder_name> -priority <val>
OCSP Caching needs to be enabled.Nonce for External Responder needs to be disabled.