Notify people that something went wrong is good. Helping them coming out of a bad situation is better. The typical 404 error page is dumb. It says sorry. It says that something went wrong. That’s it. Sometimes people make it less painful by making it beautiful or funny. That’s OK. But if you want to serve your users or customers well you should help them recover from mistakes. That’s why I have as a best practice to always include in a 404 page a call to action that brings people further. Not only on the homepage but on something which is relevant or interesting. You can do this by analyzing the keywords from the broken URL people come from, and show possible similar content. Or if you haven’t the technology to do that, be empathic. Think about what would be the most interesting thing for people to find out.
What is valid for the dumb 404 error page goes for any error message or problem communication.
If you tell a customer, you can’t find what he is searching offer him a solution.
You can tell him the address of another store where they might have that product. Or you can just explain to the customer that you don’t have that product but another one which is similar. When designing your next error message or thinking about how you handle, errors consider the following questions.
What is the solution I propose? What is the extra value I can offer in this shitty moment? What is the next step for the customer?