AmiQuote 3.21 works perfectly here (just checked AmiQuote 3.21 and ^GSPC).
Or you may not be running AQ 3.21 at all (check ABOUT window) - because AMiBroker 6.22 does NOT come with AQ3.21.
If something does work on your end it is your firewall/antivirus playing games with you and blocking normal operation of Windows and apps.