Thank you for your swift response!
Added whole GIFSquid folder (inside ScriptUI Panels) to exception, convert.exe to trusted files + set to Administrator but still no luck.
Closing completely Firewall and Antivirus made no difference.
UPDATE (Problem Solved!)
It seems there was a problem with both Avast antivirus and Comodo Firewall you can add the whole folder to be trusted and it doesn't work.
I tested few free alternatives that work and can recommend:
Firewalls: TinyWall or Simplewall
Antivirus: Bitdefender Antivirus Free or Kaspersky Cloud Antivirus
Solution: Add convert.exe to exception and something that was not mentioned here,
do the same with cmd.exe ( ! ) (you can set it for an hour or time span needed to convert file if you don't want to allow connections permanently)
It's all good now,
Thank You :)