---
title: Troubleshooting
description: What to check when responses carry no keys, a purge does not arrive, or a listing stays old.
seo:
  image: /og/troubleshooting.png
---

Start in **Settings > Advanced > Cache tags**. **Changes** shows every change, the keys it planned, which servers applied it, and each purge with its error. Every response's header shows the keys it carries.

## A response has no keys

- **Preview and signed-in requests** get no keys on purpose. Preview gets `no-store`, and a member's or user's request gets `private`.
- **A response that is not a 200**, such as a 404 or a redirect, gets `no-store` and no keys.
- **A proxy or CDN in between** may drop the header. Check the response straight from Umbraco.
- **`CacheTags:Enabled`** is `false`, or the header has another name in `CacheTags:HeaderName`.

## A purge does not arrive

Open the change in **Changes**.

- **Waiting for servers.** A server has not applied the change yet. A server that just started applies changes about a minute after start, and a server whose clock is more than 2 seconds behind is never acknowledged in time. The package sends the purge anyway after 60 seconds. Once such a server applies the change, it evicts it from its own output cache and sends the purge again, so the frontend refetches the new content.
- **No purges.** No target is configured, or every target is disabled.
- **A purge with an error.** The target answered with an error, or the package could not reach it. The package retries with backoff, and lists the purge under **Failed purges** after its last attempt. **Retry** sends it again.
- **401 from the webhook.** The secrets differ, the clocks are more than 5 minutes apart, or a proxy changes the path, which is part of the signature.

## A page stays old after a purge

- **The page was not cached with the keys.** Check that your fetch tags the entry with every key in the header. Next.js keeps at most 128 tags per entry.
- **Something else caches the page too**, such as a CDN in front of the frontend. Add that cache as a target as well.
- **The request varies by a header** that is not part of your cache key. The package sends no `Vary` header, so if you forward `Accept-Language`, `Accept-Segment` or `Start-Item`, include them in your own cache key.

## A listing stays old

The package purges listings twice, with the change and again once every server's index has it. **Waiting for index** in **Changes** means a server's index has not caught up. Right after a restart that can take over a minute. The package sends the listing purge anyway after 5 minutes.

## SQLite says the database is locked

Under load, Umbraco on SQLite can report `database table is locked` and stop answering until you restart it. SQLite allows one writer at a time, and the package writes too, as it records, acknowledges and sends each change. Use SQL Server for anything but local development.