Some troubleshooting options:

• Inspect the Cube Launcher logfiles for more details. As the error message mentions the correct Cube version I would expect it was able to access the VersionInfo.ashx endpoint but failed to download the Cube.zip file.
• Verify if the Cube file can be downloaded with a browser:
  https://training4.skyline.be/DataMinerCubeStandAlone/Cube.zip
• Verify if there are proxy settings active on the computer:
  System proxy:

  netsh winhttp show proxy

  User proxy:

  reg query "HKCU\SOFTWARE\Microsoft\Windows\CurrentVersion\Internet Settings" /f Proxy

• Verify if there is any type of antivirus/firewall enabled on the computer that may block file downloads.