When few users were trying to connect to a Citrix netscaler internally they were getting an error

socket error 10060

If you use the ICA file to check what server the machine is trying to connect to ( Go in %TEMP% and open up the latest .ica file in Notepad ) 

Check the machine can ping the server , maybe a networking ussue

Check if the server has been cloned and was using the same ID as another one ( putting it in Maintenance mode fixed the problem )