Running the Register-AzureADPasswordProtectionProxy cmdlet returned no errors, but my Agents were reporting no registered proxy service found.
Enabling the Trace log and re-running Register-AzureADPasswordProtectionProxy returns the following error:
ProxyCertificatesPopulator: Microsoft.DeviceRegistration.JOSE.JoseException: The certificate validator indicated that the signingCertificate is not trusted
at Microsoft.DeviceRegistration.JOSE.JWSHelper.ValidationWorker2(String JWS, X509Certificate2 expectedSigningCert, ICertificateValidator certValidator, X509Certificate2& signingCert, Byte[]& payload)
at Microsoft.DeviceRegistration.JOSE.JWSHelper.ValidateSignature(String JWS, ICertificateValidator certValidator, String& payload) at ServiceCommon.Converters.ProxyCertAndChainConverter.Convert(ProxyCertAndChainSerialized proxyCertAndChainSerialized) at
ServiceCommon.ServiceInfrastructure.DataPopulatorServiceComponent3.UpdateCurrentPublicDataIfNecessaryWorker(FileContentAndPath
1
latestContent, Boolean fromBackup) at ServiceCommon.ServiceInfrastructure.DataPopulatorServiceComponent3.UpdateCurrentPublicDataIfNecessary(FileContentAndPath
1
latestContent, Boolean fromBackup) at ServiceCommon.ServiceInfrastructure.DataPopulatorServiceComponent3.PopulateDirectoryFiles()
at ServiceCommon.ServiceInfrastructure.DataPopulatorServiceComponent
3.HandlePopulateDirectory(Object state, Boolean timedOut)
Proxy and AD servers are 2012 R2 with latest updates, including the Universal C update. AD is using DFSR replication.