> For the complete documentation index, see [llms.txt](https://docs.bird.com/pusher/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.bird.com/pusher/channels/channels/troubleshooting/what-can-cause-error-401-unauthorized-from-the-channels-rest-api.md).

# What Can Cause Error '401 Unauthorized' From The Channels REST API?

A 401 HTTP response from the Pusher REST API means one of the following:

1. The credentials are incorrect
2. The authentication signature is incorrect

The second reason can be caused by the time on the machine creating the signature being incorrect. This is because the signature is created with a timestamp. To remedy ensure the time is correct. See [What does the Timestamp expired response from REST API mean when triggering an event? ](/pusher/channels/channels/troubleshooting/what-does-the-timestamp-expired-response-from-the-channels-rest-api-mean-when-triggering-an-event.md)

{% hint style="info" %}
Still have questions? Please reach out to our Support team by visiting [this page](https://messagebird.com/support-center/Pusher-request-new).
{% endhint %}


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