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:

  CONFIG_TEXT: 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

  CONFIG_TEXT: ERROR: Upgrade step Plesk\Upgrade\Action_UpgradeExtensions failed with error: The file seems to have been corrupted during download. The file size is 179652 bytes instead of expected 1632896 bytes.

• 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.

Alternative solution

Determine the IP of the nearest CDN using https://dnschecker.org/#A/autoinstall-win.plesk.com and added it to C:\WINDOWS\System32\Drivers\etc\hosts on Windows or /etc/hosts on Linux. Then remove old packages info (inf3 files) from C:\ProgramData\Plesk\Installer\cache on Windows or /var/cache/parallels_installer/ on Linux.