> 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/back-in-stock-notification-cloud/common-sources-of-errors.md). # Common sources of errors 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: Finally, reinstall the app again. After that everything should work as far as possible. ### The app can't reach your shop (firewall / Cloudflare) "Back in stock notification" 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 products and notifications 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, no more back-in-stock emails are sent. You will usually notice this because notifications stop working, 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. --- # Agent Instructions This documentation is published with GitBook. GitBook is the documentation platform designed so that both humans and AI agents can read, navigate, and reason over technical content effectively. Learn more at gitbook.com. ## Querying This Documentation If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question. Perform an HTTP GET request on the current page URL with the `ask` query parameter, and the optional `goal` query parameter: ``` GET https://docs.shop-studio.io/shopware/extensions/back-in-stock-notification-cloud/common-sources-of-errors.md?ask=&goal= ``` `ask` is the immediate question: it should be specific, self-contained, and written in natural language. `goal` is optional and describes the broader end goal you are ultimately trying to accomplish on behalf of the user. GitBook uses it to tailor the answer towards what is most useful for that goal. The response will contain a direct answer to the question and relevant excerpts and sources from the documentation. Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.