His check is normal. It lasts but some seconds.
If your check returns negative, and you stay firewalled for an hour, the reason is a different one - i.e. noone is responding to your firewall check, or they're all reporting they can't contact you. People may be not able to connect to you because your line is saturated, your NAT is saturated, your food is full of saturated fats, your connections/second is saturated, or any similar reason. Or you could have changed IP and Kad didn't realize it yet, therefore telling other people to check the wrong IP (which is why I asked if your IP changed in the first place).