4xx Client errors
414 URI Too Long
The address is longer than the server accepts.
Common causes
- Huge query strings, often from sending data with GET instead of POST.
- A redirect loop that keeps adding parameters.
How to fix it
- Send large data in a POST body.
- Look for a redirect that appends to the URL each time.
Find out the moment your site returns 414
Spot Downtime monitors count this as down and alert you, since visitors see an error. (The public “Is it down?” checker treats 4xx answers from big sites as online, because many refuse automated requests.)