As I couldn’t google an answer to this one and the error was misleading, if you are using the Intune Service Connector to distribute PCKS certificates from your onprem PKI to your Intune clients and see the following error in the Connector eventlogs:

{

“Metric”:{

“Dimensions”:{

“UserId”:”c659cd5a-86e5-4733-ae58-55a896f63d53″,

“DeviceId”:”4cec597c-cd90-4077-b6c0-612a213353ef”,

“CaName”:”PATH TO CA\\CAFriendlyName”,

“TemplateName”:”Intune”,

“ElapsedMilliseconds”:”786″,

“AgentId”:”1af3469a-ef31-cfd2-3bfc-cba69a6d215d”,

“DiagnosticCode”:”0x0FFFFFFF”,

“DiagnosticText”:”We are unable to complete your request because a server-side error occurred. Please try again. [Exception Message: \”DiagnosticException\”] [Exception Message: \”IssuePfx – The submission failed\”]”

},

“Name”:”PkcsCertIssue_Failure”,

“Value”:0

}

}

And this error on your CA:

EventId 22:

Active Directory Certificate Services could not process request 136204 due to an error: Error 0xc8000211 (ESE: -529).  The request was for COMPUTERNAME.  Additional information: Error Parsing Request

Ensure you restart the Active Directory Certificate Services service on your CA. This is not required as per the documentation, but was surely required in my environment.