Korell wrote he tried the code with "several phones" and tried manually entering the web address, but he received the same result each time.
Heinz apologized to Korell, saying the company's ownership of the website expired after the 2012-2014 contest came to a close.
"Even if the bottle was a leftover, it's still in lots of households," Korell said in a comment. "It's incomprehensible that you didn't reserve the domain for one or two years. A .de domain name really doesn't cost the Earth."
The ketchup company offered Korell a custom-designed bottle free of charge by way of compensation and said it would gladly accept "suggestions for the implementation of future campaigns."
German news site Bild said Korell was also offered a free membership by the porn site that took over the domain.