Rendering errors – Lob

Source Link: https://help.lob.com/print-and-mail/designing-mail-creatives/creative-formatting/rendering-errors
# Rendering errors Lob occasionally encounters problems with the creative when rendering mailpieces; this can occur with either PDFs or HTML. To avoid sending out erroneous mailpieces, Lob provides visibility of these errors, with proactive notification of rendering errors in place. {% hint style="success" %} We always recommend testing; and where possible, sending yourself a printed mailpiece. {% endhint %} ## PDF **Lob will fail incorrectly formatted PDFs.** [See our PDF preflight checklist here](pdf-preflight-checklist) to ensure your file will process through our rendering engine. ## HTML **Lob will fail HTML that includes inaccessible assets (images, fonts, any other URLs):** * the link to an asset is incorrect * the asset referenced in the file is missing * Lob has not been given the correct permission to access the asset (ensure that the link is set to public viewing, and not private) * when a remote asset references a local asset (for example, a remote asset is at www.example.com which then references something local in that directory) * slow or under-resourced server providing the asset (we recommend using a performant service, such as Amazon S3, to host the content) ### HTML Template Preview If your HTML contains an inaccessible asset, your HTML preview will error. Details of the error will be displayed in a future release.

### In the Campaigns UI flow * **When creating your Campaign, you **_**may**_** be notified when you generate a Creative Proof** (if the sample mailpiece that is rendered results in an error); if this occurs you should troubleshoot against the above list.

* **After placing the order, you will be notified in the dashboard,** and the reason for the error will be provided (click to enlarge):

* The Lob support team will proactively reach out. ### API users * API customers will receive an error notification in the API response. * The Lob support team will proactively reach out. ## Webhooks Webhooks users can subscribe to receive notifications of failed orders. (Learn more about [using webhooks](../../getting-data-and-results/using-webhooks) here.) 1. Under Webhooks in the dashboard, in the Live environment, click Create. 2. Check \[formfactor].failed; click Create.

If subscribed to postcard.failed, letter.failed, and/or check.failed, and Lob fails an order during rendering, the following error messages are possible: _"Rendering failed due to asset issue:_ * _The requested asset was not found: \"_ * _The requested asset is not permitted: \"_ * _Authentication is required to access the requested asset: \"_ * _An internal server error occurred for: \"_ * _The requested asset timed out: \"_ * _An unknown server error occurred for: \"_ * _The requested service is unavailable for: \"_ * _An unknown error occurred for: \"_ If not one of the most common errors above, or a PDF failure, _"try re-render”_ will be returned.

{% hint style="info" %} If you are unable to resolve the error, please reach out to [support@lob.com](https://email:support@lob.com) {% endhint %}