This is what I get:
http://autoinstall.plesk.com/Parallels_Installer/parallels_installer_Ubuntu_14.04_armv7l
Resolving autoinstall.plesk.com (autoinstall.plesk.com)... 185.59.222.22
Connecting to autoinstall.plesk.com (autoinstall.plesk.com)|185.59.222.22|:80... connected.
HTTP request sent, awaiting response... 404 Not Found
2017-05-25 18:52:00 ERROR 404: Not Found.
ERROR: Unable to run Plesk Installer. Possible reasons:
1) You are trying to run Plesk Installer on an unsupported OS. Your OS is Ubuntu-14.04. The list of supported OS is at
Software Requirements for Plesk
2) Temporary network problem. Check your connection to autoinstall.plesk.com, contact your provider or open a support ticket.