The command Set-IRMConfiguration -ExternalLicensingEnabled $true failed

I'm using following URL to set RMS on the exchange server 2013,

http://windowstechpro.com/part-3-how-to-enable-irm-ad-rms-in-exchange-2013/

The Set-IRMConfiguration command is failing with following errors,

[PS] C:\Windows\system32>Set-IRMConfiguration -InternalLicensingEnabled $true
The remote name could not be resolved: 'rms01.domain.local' ---> Failed to get Server Info from
https://rms01.domain.local/_wmcs/certification/server.asmx.
    + CategoryInfo          : InvalidOperation: (:) [Set-IRMConfiguration], Exception
    + FullyQualifiedErrorId : [Server=AS-EXCH15,RequestId=8a7f8713-90e0-456c-b79b-1902919993ca,TimeStamp=4/28/2018 10:
   22:13 AM] [FailureCategory=Cmdlet-Exception] FE9C3535,Microsoft.Exchange.Management.RightsManagement.SetIRMConfigu
  ration
    + PSComputerName        : as-exch15.domain.local

The test-IRMConfiguration is failing with following errors,

[PS] C:\Windows\system32>Test-IRMConfiguration -Sender jrnlmbx@domain.local


Results : Checking Exchange Server ...
              - PASS: Exchange Server is running in Enterprise.
          Loading IRM configuration ...
              - PASS: IRM configuration loaded successfully.
          Retrieving RMS Certification Uri ...
              - PASS: RMS Certification Uri: https://rms01.domain.local/_wmcs/certification.
          Verifying RMS version for https://rms01.domain.local/_wmcs/certification ...
              - WARNING: Failed to verify RMS version. IRM features require AD RMS on Windows Server 2008 SP2 with the
          hotfixes specified in Knowledge Base article 973247
          (http://go.microsoft.com/fwlink/?linkid=3052&kbid=973247) or AD RMS on Windows Server 2008 R2.
          ----------------------------------------
          Microsoft.Exchange.Security.RightsManagement.RightsManagementException: Failed to get Server Info from
          https://rms01.domain.local/_wmcs/certification/server.asmx. ---> System.Net.WebException: The remote name
          could not be resolved: 'rms01.domain.local'
             at System.Net.HttpWebRequest.GetRequestStream(TransportContext& context)
             at System.Net.HttpWebRequest.GetRequestStream()
             at System.Web.Services.Protocols.SoapHttpClientProtocol.Invoke(String methodName, Object[] parameters)
             at Microsoft.Exchange.Security.RightsManagement.SOAP.Server.ServerWS.GetServerInfo(ServerInfoRequest[]
          requests)
             at Microsoft.Exchange.Security.RightsManagement.ServerWSManager.ValidateServiceVersion(String
          featureXPath)
             --- End of inner exception stack trace ---
             at Microsoft.Exchange.Security.RightsManagement.ServerWSManager.ValidateServiceVersion(String
          featureXPath)
             at Microsoft.Exchange.Management.RightsManagement.IRMConfigurationValidator.ValidateRmsVersion(Uri uri,
          ServiceType serviceType)
             at Microsoft.Exchange.Management.RightsManagement.IRMConfigurationValidator.TryGetRacAndClc()
          ----------------------------------------

          OVERALL RESULT: PASS with warnings on disabled features

Any suggestion would be great and I really appreciate you help!