"I want to activate my Content Filter / Antivirus / etc. license, I want to regsiter my unit at MyZyxel.com, but I just only get the error message "Connect to myZYXEL.com server has failed." when clicking on "Service License Fresh."
In that case you might have not setup a DNS forwarder to let your USG be able to to resolve domain names. Please try this:
If this fails, try: