So by 11.1.x code that is the code base running on the netscaler appliances that offer up the gateway login page. I am not a user but an engineer for a large Health System. Our users that have Avast and AVG are suffering from the same issue where they are unable to load our Citrix gateway from their home PC's with either Secure DNS or Web Shield / Online shield enabled. The operating systems range from 7, 8.1, to 10. Our domain resides on no Blacklist nor do our public IP's fail an IP rep test. The latest update didnt resolve the issue nor did a fresh install with the latest installer. The tests were done on a 64 bit Windows 10 box with a fresh install, a Windows 7 32bit box with a fresh install, and a Windows 7 64 bit box with a fresh install.
To this point I have been unable to actually speak with anyone from Avast. So at this point we are instructing our users that if they require remote access that they cant use Avast or AVG.
Thank you very much for replying to the post.