Why Did My Kling Video Fail? Causes and Fixes

A Kling video usually fails for one of four reasons: the prompt or an input image breaks a content rule, an image is too small, too narrow or in an unsupported format, the request sends a setting the model doesn't take, or the run times out. This applies to Kling 3.0 and Kling 4.0, Kuaishou's video models, wherever you run them, including on Makernice.

Why did my Kling video fail?

Kling videos fail mostly because of content moderation, image specs, unsupported settings or timeouts. Find what you see in the left column. The first five rows are content and image problems, the last two are settings and time. The error codes are what the Makernice API and web tools return; in other apps the wording differs, but the causes are the same.

What does "try a different prompt" mean on Kling?

"Try a different prompt" means Kling refused the request, so sending the same prompt again is unlikely to help. Kuaishou doesn't publish an explanation of that exact message that we could find. The closest official rule is Kling's Community Guidelines, effective September 8, 2026, which list eight categories of prohibited content and allow Kling to "prohibit the generation of content" that breaks them. These are the categories that most often catch video prompts:

• Sexually explicit content, in any form, including text, images or video.
• Content involving minors in a harmful way, including animated or digitally created media.
• Infringing other people's rights, such as their reputation, privacy or likeness.
• Intellectual property, such as copyrighted works, trademarks or imitated brand material.

Content that Kling's own rules block is likely to be refused on other platforms that run Kling too. Makernice also has its own moderation, and it can't be turned off. We don't help get around either one. Rewrite the scene so it stays inside the rules, or remove the subject that triggers the refusal.

Why did Kling fail to upload my image?

Kling rejects images that are too small or too stretched, and some files can't be fetched or read at all. These rules apply to every Kling 3.0 and Kling 4.0 mode that takes an image (image-to-video, first and last frame, and Kling 4.0 reference-to-video):

• Size: the shorter side must be at least 300 px; the longer side has no upper limit.
• Shape: width divided by height must be between 0.4 and 2.5, so nothing wider than 5:2 or taller than 2:5.
• File: a still JPEG, PNG or WebP of at most 10 MB; animated WebP and GIF aren't supported.
• Link: a public https URL of up to 2,048 characters that serves the image itself. Redirects aren't followed, so share links and short links fail.

When an image breaks the size or shape rules, Kling rejects it: the generation fails with error.code invalid_request and the hold is released. Crop or resize the image to fit, then get a new quote and create a new generation. When the file itself can't be used, error.input also names the image (image_url, last_image_url or reference_images[0]). The file and link rules are in the API docs.

Why is Kling 3.0 not working with my settings?

Usually because the request uses something Kling 3.0 doesn't support. The four Kling models on Makernice accept different modes, lengths and prompt sizes:

Three more settings catch people out. Kling 3.0 text-to-video accepts aspect_ratio 16:9, 9:16 or 1:1. Kling 4.0 text-to-video and reference-to-video accept 16:9, 9:16, 1:1 or 21:9. Image-to-video and first and last frame don't take it, so sending aspect_ratio there returns 400 invalid_request. Kling 3.0 has no resolution field: Pro is billed as 1080p and Standard as 720p, while Kling 4.0 takes 720p or 1080p. Every Kling video comes with sound, and there is no setting to turn it off.

Does Kling reject photos of real people?

Kling can reject photos of real people when they fail moderation. Kling's guidelines protect people's likeness and privacy, An image that Kling itself refuses comes back on Makernice as content_rejected with reason model. An image stopped by Makernice's own input check comes back with reason input_image. Makernice's own Acceptable Use Policy adds stricter rules for uploads: you may only upload images you own or have permission to use, everyone shown must be you or an adult (18 or older) who has clearly agreed, and photos of public figures, celebrities or performers aren't allowed even if you believe you have their consent. If you can't meet these rules, use a designed or AI-generated character.

Is a failed Kling generation charged on Makernice?

No. The hold is released in full — you're never charged for a failed generation. Note: if a finished output is blocked by output moderation for a policy violation, the run is still charged. You can contact support for a manual review. Creating a generation only holds the quoted amount, and a released hold never left your balance. A prompt blocked at creation holds nothing at all. See the failed generations table in the docs and the billing examples.

What if my Kling video is stuck generating?

Keep polling: a video moves from queued to generating, then to moderating (generation is finished and the amount is charged; the outputs are in a safety check, so keep polling), and ends as succeeded, failed or canceled. A checking status means we're confirming the result, and the amount stays held until it's resolved. Every status is in the status docs. On Makernice a video generation can run for at most 60 minutes; after that it fails with error.code timeout and the hold is released. If your own client times out while creating, don't create a second generation. Retry the create with the same Idempotency-Key and you get the original generation back.

Where do these Kling facts come from?

Checked on November 9, 2026. Next step: once the request is fixed, write a prompt Kling follows with the Kling 4.0 prompt guide, or get first frames right with the image-to-video and first and last frame guide. Running Seedance too? See why Seedance videos fail.