An extensive list of resources and guides for fixing error codes is available on the MakeUseOf website. Because so many programs and systems use unique error codes to signify the type of problem a computer or site may be having, this list only includes resources for the most common errors.
The article "Top 10 Websites for Error Codes and Troubleshooting" on the MakeUseOf website provides a list of the ten most useful websites and tools for troubleshooting common error codes. This list covers a variety of code types, including Microsoft Windows, Oracle, HTTP, Flash and SMTP. One of the listed resources is ErrorHelp, which provides search results for Windows, Apple and Linux errors in addition to a large database of solved errors.
Many of the websites on the MakeUseOf list offer a search feature where users can enter their error code to receive a detailed description of the code's meaning and potential causes. Not all of the resources offer troubleshooting information, but figuring out the meaning of an error code can help determine the solution. The list does mention using Google or another search engine as an additional tool, stating that a generic search for most errors provides useful results from a number of sources, from official troubleshooting pages to forums and question and answer websites. For more troubleshooting information, the websites Kioskea.net and DigitalOcean offer lists of fixes for some common Windows and HTTP error codes.