We have several SSL certificates which we would like to monitor. The internal CA is publishing a CRL and this file can be reached from PRTG Server (has been tested). The CRL is mentioned in the certificate, this also has been checked. The internal CA is also in the trusted root as this channel is ok.
But the SSL certificate sensor is still in the warning state for all internal CAs:
Warning by lookup value 'Unable to check revocation status' in channel 'Revoked' (OK. Certificate Common Name:[...])