Unable to install or update Plesk: Operation too slow. Less than 500 bytes/sec transferred the last 30 seconds

Symptoms

• Unable to update or upgrade Plesk. The following error is shown:

  Error: Failed to download the file http://autoinstall-win.plesk.com/PANEL-WIN_17.8.11/dist-windows/plesk-backend_mu008.msi: Operation too slow. Less than 500 bytes/sec transferred the last 30 seconds

• Connection to http://autoinstall-win.plesk.com/ is possible via telnet:

  # telnet autoinstall-win.plesk.com 80
  Trying xx.xx.xxx.xx...
  Connected to autoinstall-win.plesk.com.

• Download from another sources is very slow or not possible as well.

• On Windows, it is not possible to download *.msi files manually via browser, for example the file from the error http://autoinstall-win.plesk.com/PANEL-WIN_17.8.11/dist-windows/plesk-backend_mu008.msi

Cause

Network connection quality or bandwidth issue.

Resolution

Contact ISP provider to fix the issue with the network connection quality or bandwidth.