Errors

Rejected submissions answer with an HTTP status and, for JSON requests, a body like this:

{ "ok": false, "error": "rate_limited", "message": "Too many requests. Try again shortly" }

Branch on error, which never changes. message is written for the people filling in your form, so you can show it to them as is. Browser form posts get the same outcome as a page with a link back to your site.

Errors from the API that manages forms and submissions look different. See API errors.

Error codes

Status	`error`	Message	What to do
`400`	`too_many_files`	Too many files attached	Send at most 5 files per submission.
`402`	`quota_exceeded`	This form has reached its monthly submission limit	The team used its monthly submissions. Upgrade or wait for next month.
`403`	`origin_not_allowed`	This form does not accept submissions from this website	Add the site to the form's allowed websites.
`403`	`captcha_failed`	Captcha verification failed. Complete the captcha and try again	Send a valid Turnstile token. See Cloudflare Turnstile.
`404`	`form_not_found`	Form not found	Check the key in your endpoint. It may have been rotated or the form deleted.
`405`	`method_not_allowed`	This is a nisuform form endpoint...	Send a `POST` request.
`413`	`payload_too_large`	Submission too large	Keep the request under 200 KB, or 25 MB with file uploads.
`413`	`attachment_too_large`	A file exceeds the upload size limit	Send smaller files, or raise Size limit per file.
`415`	`unsupported_media_type`	Unsupported content type	Send JSON, URL-encoded or multipart data, and valid JSON.
`415`	`attachment_type_rejected`	A file type is not allowed	Send JPEG, PNG, WebP, GIF or PDF files.
`422`	`empty_submission`	The submission is empty. Fill in the form and try again	Send at least one non-empty field or a file.
`423`	`form_closed_manual`	This form is closed and not accepting submissions	The form is paused. Resume it in Settings, General.
`423`	`form_max_submissions`	This form has reached its maximum number of submissions	Raise or clear Maximum submissions.
`423`	`form_auto_close`	This form closed automatically on its scheduled date	Clear or move the Close on date.
`429`	`rate_limited`	Too many requests. Try again shortly	Wait a minute, or the seconds in the `Retry-After` header when you can read it. See rate limits.
`500`	`upload_failed`	Uploading your attachment failed. Please try again	Nothing was stored. Try again.
`500`	`internal_error`	Something went wrong	Try again. If it keeps happening, contact support with the `x-request-id` header.

On Pro, the three 423 errors use your own Closed message when you set one. See Pause and close a form.

Errors that look like success

Some submissions are dropped on purpose but still answer 200 with { "ok": true } and no submissionId, so bots can't tell they were caught:

The _gotcha honeypot had a value.
_elapsed was under 2 seconds.
The sender's IP address or country is blocked for the form.

If your own test submissions are missing from the inbox, check these first. See Troubleshooting.

Validation problems are not errors

Answers that don't match your form's fields don't cause an error. The submission is stored and marked in the inbox. See Fields and validation.

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Errors that look like successCopy Anchor Link

Validation problems are not errorsCopy Anchor Link

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Error codes

Errors that look like success

Validation problems are not errors