Logs being sent using the Windows Event Collector (WEC) produce the following error:
error when reading request headers: tls: client didn't provide a certificate
Please ensure that the correct certificate is on the machine, that the network service account has access to read the private keys, and that the Windows Remote Management service is set to be able to authenticate using a certificate.
For more information on configuring the Windows Event Collector, please see the Windows Event Collector administrative guide.
If the above is set correctly, please run a packet capture on the endpoint to see whether or not the logs contain a certificate. If the logs show a length of 0 for the certificate, than no certificate is attached correctly and the appropriate team who manages the site's Windows certificates will need to be engaged.