When this happens, the "Certificate Chaining Engine" cannot verify if a certificate has been revoked, which can cause authentication failures for VPNs, Wi-Fi (802.1X), and secure web services. Common Causes of the Error How to fix PKI View CDP location #2 error - Microsoft Q&A
The "CDP Location Unable to Download" error is a critical warning in Windows PKI environments, typically appearing in the management console. It indicates that the system cannot access or retrieve the Certificate Revocation List (CRL) from its designated CRL Distribution Point (CDP) . cdp location unable to download