Parallels 11 activation on OS X 10.11 - network error

Wanted to instal trial version of Parallels 11 on OSX 10.11. Have the same issue as the other guys on OSX 10.13... Network error.
Parallels 11 is the highest version which is working on the system I have.
iMac 2007, OSX 10.11.6
fresh system installation
trying to install PD downloaded from KB:
https://kb.parallels.com/5802

No virus software installed, firewall off, nothing that could make impact to network traffic filtering.
Still have an error.
Have checked KB, terminal woo shoo done with no improvement.
Still have an error.
Network is working properly, can display any web page on Safari, Parallels including.
Still have an error.

I have a license for each below:
Parallels Desktop 3
Parallels Desktop 4
Parallels Desktop 5
Parallels Desktop 6
Parallels Desktop 7
Parallels Desktop 15 (upgrade from 5)
Parallels Desktop 20 (upgrade from 15)

Any clue?