ask ko lang, is that your own PC? or sa company niyo and you been trying to run YM and CHIKKA?
probably not a firewall issue yan, its a software restriction policies, kung sa company niyo yang PC di mo pwede maayos yan, if own PC mo yn try to check this
->go to run command
->type gpedit.msc
->expand "computer configuration"
->check "Software Restriction Policies" if YM and chicka programs was set in there.
-> you can expand software restriction policies by right clicking it then set new policies / rules.
let me know if still cant fix the issue.