> For the complete documentation index, see [llms.txt](https://platform9.com/kb/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://platform9.com/kb/pmo/solution/used-old-installer-to-authorize-host-error-authorizing-host-ple.md).

# Used Old Installer to Authorize Host "Error Authorizing Host. Please Contact Support

## Problem

An attempt to authorize a new host using an installer that was downloaded prior to an upgrade of the Management Plane's current version causes the following error to appear in the Clarity UI: "Error Authorizing Host. Please Contact Support"

## Environment

* Platform9 Managed OpenStack - All Versions

## Cause

The installer from the previous version of Platform9 Managed OpenStack on the Management Plane will not contain the correct packages to properly authorize.

## Resolution

1. [Deauthorize](https://docs.platform9.com/support/how-to-deauthorize-a-host/) the host.
2. Uninstall the existing version of Hostagent.

{% tabs %}
{% tab title="None" %}

```none
# sudo apt-get purge pf9-hostagent
```

{% endtab %}
{% endtabs %}

3. [Download a fresh installer package](https://docs.platform9.com/openstack/infrastructure/add-host/) from the Clarity UI.
4. Install the new package on the host and authorize from the UI as normal.


---

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