> For the complete documentation index, see [llms.txt](https://docs.sharelogic.com/unifi/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.sharelogic.com/unifi/4.0/troubleshooting/integration-responses/message-has-already-been-processed.md).

# Message has already been processed

{% hint style="danger" %}
`Message has already been processed`
{% endhint %}

This error occurs because the request sent to Unifi references a message ID that corresponds to an existing transaction in the receiving Unifi system. This usually happens when the receiving Unifi systems integration has been linked to two separate systems, i.e. a dev and UAT system, and therefore your message IDs are duplicated.

Ensure that the message IDs you are sending are unique, and/or you remove the preciously duplicated transactions in the receiving system.