Dell Updates using SCUP error 0x800b0004

Dear, 

When trying to deploy Dell updates using SCCM (and SCUP integration) we constantly receive the following error:

WUAHandler.log: "Failed to download update to the WUAgent datastore. Error = 0x800b0004" 

UpdatesHandler.log: "Failed to initiate install of WSUS updates, error = 0x800b0004"

"Failed to start WSUSUpdate, error = 0x800b0004"

The SCUP certificate has been imported in the Trusted Root CA & Trusted publisher store on the WSUS (SCCM) server and the server we are using to test the deployment.

Any ideas?

Best regards,

B.