4xx Client errors
413 Content Too Large
The request body is bigger than the server accepts.
Common causes
- Uploading a file over the size limit.
How to fix it
- Raise the limit (e.g. client_max_body_size in nginx, upload_max_filesize in PHP) or upload smaller files.
Find out the moment your site returns 413
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.)