What causes a 400 Bad Request response? And how to fix it?
Posted: Sun Feb 09, 2025 5:15 am
There are a number of reasons why your browser might trigger a 400 Bad Request response. The server or your browser client might not indicate the cause, so it’s best to troubleshoot these issues:
URL string syntax error
If you see this error, it means you have entered the wrong URL. This is the most common cause of 400 Bad Requests. You can also have "malformed URL" or "illegal" characters in the URL string.
Malformed URLs typically occur when the URL string contains malta mobile database extra percent signs %. Illegal characters are characters not normally found in URLs for example, "}".
How to fix: Double-check the URL for typos, illegal characters, or remove the double %% characters and try again.
Corrupted or invalid cookies
Cookies are information stored on your computer about websites you have visited. The next time you visit that website, it will use the data stored in the cookie to load faster for you.
If the cookies you have are stale, expired, or corrupted, you may receive a Bad Request error.
URL string syntax error
If you see this error, it means you have entered the wrong URL. This is the most common cause of 400 Bad Requests. You can also have "malformed URL" or "illegal" characters in the URL string.
Malformed URLs typically occur when the URL string contains malta mobile database extra percent signs %. Illegal characters are characters not normally found in URLs for example, "}".
How to fix: Double-check the URL for typos, illegal characters, or remove the double %% characters and try again.
Corrupted or invalid cookies
Cookies are information stored on your computer about websites you have visited. The next time you visit that website, it will use the data stored in the cookie to load faster for you.
If the cookies you have are stale, expired, or corrupted, you may receive a Bad Request error.