# AFC error messages

Source: https://developer.avalara.com/products/communications/integration-guides/communications-integration/lld8429045465714/

Guide: Communications

# AFC error messages

We’ve designed the AFC error messages to tell you what went wrong during an API call, what you can do about it, and how to proceed.

When an AvaTax API call produces an error, it responds using the standard [HTTP error response codes](https://en.wikipedia.org/wiki/List_of_HTTP_status_codes).

-   Response codes between 500 and 599 refer to internal errors within AvaTax itself. Each internal error is automatically logged and reported to our development team for triage.
-   The remaining response codes are Client Errors, and they indicate a mistake in an API call.

You can learn more about the AFC error codes in the [Avalara for Communications REST v2 Developer Guide](https://developer.avalara.com/communications/dev-guide_rest_v2/reference/general-errors/).