---
title: "Troubleshooting Content Library Uploads"
description: "Learn how to fix common upload failures in the Postpone Content Library, including unsupported file types, size limits, and expired sessions."
canonical_url: "https://help.postpone.app/content/media-library/troubleshooting-uploads"
---
# Troubleshooting Content Library Uploads

> Learn how to fix common upload failures in the Postpone Content Library, including unsupported file types, size limits, and expired sessions.

If a file fails to upload to the Content Library, one of the following is usually the cause.

## Unsupported file type

The Content Library only accepts specific file formats.

<table>
<thead>
  <tr>
    <th>
      Type
    </th>
    
    <th>
      Supported formats
    </th>
  </tr>
</thead>

<tbody>
  <tr>
    <td>
      Video
    </td>
    
    <td>
      .mp4 (preferred), .mov, .webm, .mkv
    </td>
  </tr>
  
  <tr>
    <td>
      Image
    </td>
    
    <td>
      .jpeg / .jpg, .png, .heic / .heif, .webp
    </td>
  </tr>
  
  <tr>
    <td>
      GIF
    </td>
    
    <td>
      .gif
    </td>
  </tr>
</tbody>
</table>

If your file is in a different format (e.g. .avi, .wmv, .tiff, .bmp), convert it to a supported format before uploading.

## "Signature expired" error

If you see a **"Signature expired"** error, the upload session has timed out. Upload sessions are only valid for **2 hours**. Leaving the Content Library page open for more than 2 hours without refreshing will cause this error.

**Fix:** Refresh the page. This starts a new upload session and your uploads will proceed normally.

<note>

Files that were successfully uploaded before the session expired are safe — they remain in your Content Library.

</note>


## Sitemap

See the full [sitemap](https://help.postpone.app/sitemap.md) for all pages.