> For the complete documentation index, see [llms.txt](https://docs.shop-studio.io/shopware/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.shop-studio.io/shopware/extensions/tree-per-order/common-sources-of-error.md).

# Common sources of error

APP\_URL is wrong in the .env

On the server there is an .env file where an important URL is stored at the variable APP\_URL. This URL is used so that the external app contains a URL from your Shopware store for communication back (this is an external Shopware cloud app).

Unfortunately, this URL is almost always set incorrectly for self-hosted stores - already by the installer. The URL could be similarly wrong as here:

```
APP_URL="http://127.0.0.1"
```

It is important to use the URL of the store for the correction. It is also important to note http & https. In some cases, it can also be a different URL to the admin of the store (eg Shopware PWA or multiple store domains within one installation). Correct would be e.g.

```
APP_URL="https://www.my-shop.com"
```

After the change, save the file once and clear the store cache. Now a new window will appear in the admin because the URL has changed. Here would be a way to tell all external cloud apps that the URL has changed because the store has "moved". There is a little more at this point: <https://developer.shopware.com/docs/guides/plugins/apps/app-base-guide#handling-the-migration-of-shops>

Finally, reinstall the app again. After that everything should work as far as possible.

### The app can't reach your shop (firewall / Cloudflare)

"Tree per Order (Cloud)" is an external cloud app: it runs on our servers and talks to your shop through Shopware's API, which has to be reachable from the outside. The app uses this interface to keep your orders and tree donations up to date.

Many shops protect this interface with a firewall, a security service, or a CDN such as Cloudflare. That is a good thing in general — but if your shop makes a lot of changes during the day, our app sends and receives many API calls, and these protection systems can mistake our regular requests for unwanted traffic and block them. When that happens, our app no longer gets through to your shop and updates stop arriving — for example, donations are no longer registered (no new trees are planted).

You will usually notice this because donations stop being registered, and in your server logs a `403 Forbidden` message appears.

To prevent this, add our IP addresses to the allowlist (whitelist) in your firewall, your security service, or Cloudflare. Our requests are then always recognised as trusted and never blocked:

```
74.220.51.43
74.220.51.44
74.220.51.45
```

If you are not sure how to do this, your hosting provider — or whoever set up Cloudflare for you — can add these three addresses in a minute.