remotion-dev/remotion · error · InvalidArgumentException

Cannot cancel render {$renderId}: The render was not started

Error message

Cannot cancel render {$renderId}: The render was not started with enableCancellation: true.

What it means

Thrown by PHPClient::cancelRenderOnLambda() (packages/lambda-php/src/PHPClient.php). Before writing the cancellation flag, the method downloads renders/{renderId}/progress.json from the render bucket and requires cancellationEnabled to be exactly true. Remotion Lambda makes cancellation opt-in (it adds overhead to the render), so only renders started with enableCancellation: true can be canceled; anything else is rejected with this InvalidArgumentException.

Source

Thrown at packages/lambda-php/src/PHPClient.php:311

        $result = $this->invokeLambdaFunction($payload);
        return $this->handleLambdaResponseProgress($result);
    }

    public function cancelRenderOnLambda(string $renderId, string $bucketName): void
    {
        try {
            $progress = json_decode(
                $this->readProgressFromS3($bucketName, "renders/{$renderId}/progress.json"),
                true,
                512,
                JSON_THROW_ON_ERROR
            );
        } catch (\Throwable $exception) {
            throw new Exception("Could not read progress for render {$renderId}: {$exception->getMessage()}", 0, $exception);
        }

        if (($progress['cancellationEnabled'] ?? false) !== true) {
            throw new InvalidArgumentException(
                "Cannot cancel render {$renderId}: The render was not started with enableCancellation: true."
            );
        }

        try {
            $this->writeCancellationToS3(
                $bucketName,
                "renders/{$renderId}/cancel.json",
                json_encode(
                    ['cancelledAt' => (int) floor(microtime(true) * 1000)],
                    JSON_THROW_ON_ERROR
                )
            );
        } catch (\Throwable $exception) {
            throw new Exception("Could not cancel render {$renderId}: {$exception->getMessage()}", 0, $exception);
        }
    }

View on GitHub (pinned to 10db9de073)

Solutions

1. For any new render, opt in at render time: call $renderParams->setEnableCancellation(true) (or pass enableCancellation: true when constructing RenderParams) before renderMediaOnLambda().
2. For the currently running render there is no remedy - it was not started cancellable. Let it finish, or abandon its output and start a new render with the flag enabled.
3. Verify the flag took effect: download renders/{renderId}/progress.json from the render bucket and confirm cancellationEnabled is exactly true.
4. If progress.json has no cancellationEnabled field at all, your deployed Remotion Lambda functions are older than the PHP client - update them (npx remotion lambda update) so client and functions match.

Example fix

// before
$renderParams = new RenderParams();
// ... composition, codec, etc. - enableCancellation never set (defaults to false)
$response = $client->renderMediaOnLambda($renderParams);
$client->cancelRenderOnLambda($response['renderId'], $response['bucketName']); // throws

// after
$renderParams = new RenderParams();
$renderParams->setEnableCancellation(true);
$response = $client->renderMediaOnLambda($renderParams);
$client->cancelRenderOnLambda($response['renderId'], $response['bucketName']); // works

// Render time - decide cancellability before starting, in one factory
$renderParams = new RenderParams();
$renderParams->setEnableCancellation(true); // required for cancelRenderOnLambda()
$response = $client->renderMediaOnLambda($renderParams);

// Cancel time - optionally verify progress.json before calling cancel
$progress = json_decode(
    file_get_contents("https://{$bucketName}.s3.{$region}.amazonaws.com/renders/{$renderId}/progress.json"),
    true
);
if (($progress['cancellationEnabled'] ?? false) !== true) {
    // do not call cancelRenderOnLambda() - it will throw
}

try {
    $client->cancelRenderOnLambda($renderId, $bucketName);
} catch (\InvalidArgumentException $e) {
    if (str_contains($e->getMessage(), 'enableCancellation')) {
        // render is not cancellable - surface a clear message to the user
    } else {
        throw $e;
    }
}

When it happens

Trigger: Calling $client->cancelRenderOnLambda($renderId, $bucketName) for a render started via renderMediaOnLambda() whose RenderParams left enableCancellation at its default of false (packages/lambda-php/src/RenderParams.php sets protected $enableCancellation = false), i.e. the params object was never configured with setEnableCancellation(true).

Common situations: Starting a long render and only then deciding to cancel it; passing enableCancellation into inputProps or the wrong options array instead of RenderParams; helper code copied from a template that predates the option; deployed Remotion Lambda functions older than the PHP client so progress.json never contains the field.

Related errors

• Could not read progress for render {$renderId}: {$exception-
• Could not cancel render {$renderId}: {$exception->getMessage
• Could not read progress for render {render_id}: {error}
• Cannot cancel render {render_id}: The render was not started
• Cannot cancel render #{render_id}: The render was not starte

AI-assisted analysis of remotion-dev/remotion@10db9de073 (2026-08-22). Data as JSON: /api/errors/76121aed90cbdaf0. Report an issue: GitHub.