You probably have some kind of internet restrictions.
Check your Company Policy
As a workaround, you can download the Help On-Line Documentation from Aveva, save it somewhere and modify the custom-evars file as here below (it is just an example):
set AVEVA_DESIGN_HELP_HOST=file://D:\AVEVA\E3D3.1\WebHelp\
You probably have some kind of internet restrictions.
Check your Company Policy
As a workaround, you can download the Help On-Line Documentation from Aveva, save it somewhere and modify the custom-evars file as here below (it is just an example):
set AVEVA_DESIGN_HELP_HOST=file://D:\AVEVA\E3D3.1\WebHelp\