Troubleshooting video uploads in Buffer

The most common issues come from using videos outside of the suggested requirements, so be sure to check the limits below before proceeding to other troubleshooting steps!

In this article:

1. Check your video format and requirements first
2. My video is stuck at 0% or won't upload to Buffer
3. Video size, length, and aspect ratio by network
4. Custom thumbnails, cover images, and video titles
5. Notification publishing, automatic publishing, and "Sent but not live"
6. Why does my video quality look lower after publishing through Buffer?
7. Posting videos through the API, Zapier, Make, or n8n
8. Platform limits and what isn't supported
9. Helpful tools for optimizing video files
10. Quick checklist

Check your video format and requirements first

Before uploading, make sure your video meets the specifications below. Most upload issues are caused by the video codec (the way the file is encoded), rather than its file size. You can check your video’s format, codec, resolution, and file size using a free tool such as MediaInfoOnline.

• Codec: H.264. This is the most important setting. Video recorded on an iPhone or Mac is usually HEVC (H.265), which often fails to upload to Buffer. Re-encode to H.264 if you're not sure.
• Format: MP4, MOV, AVI, or M4V. MP4 (H.264) is the most reliable.
• Resolution: up to 1080p (1920px on the longest side). Videos larger than 1080p are downscaled during processing. 720p (1280×720) uploads and processes the fastest.
• Video bitrate: ideally under 25 Mbps (aim for 20–25 Mbps or lower for 720p), especially for Threads, Facebook, LinkedIn, and X/Twitter.
• Audio: AAC codec, bitrate 128–192 kbps.

Maximum file size (varies by network):

• 40MB for Mastodon
• 100MB for Bluesky
• 300MB for Instagram
• 1GB for Facebook, X/Twitter, LinkedIn, Pinterest, TikTok, and Threads
• 10GB for YouTube Shorts

Avoid raw or high-end camera formats such as ProRes, HEVC (H.265), AV1, or RED. These can fail even when the file size and length are within limits.

My video is stuck at 0% or won't upload to Buffer

If a video stays at 0%, hangs during upload, or shows an error such as “Thumbnail generation failed for [filename]” or “Upload stalled for 60 seconds, aborting,” the issue is occurring while the video is being uploaded to Buffer, before the post is sent to the social network. The most common cause is the video codec.

Start by re-encoding videos from HEVC (H.265) to H.264. Buffer uses your browser’s video decoder to generate the upload preview, and some browsers, especially Chrome on older macOS versions or restricted work and virtual desktop environments, cannot decode HEVC, ProRes, or AV1 files. When this happens, the upload may remain at 0% or fail during thumbnail generation.

Because iPhones and Macs often record video in HEVC by default, this is a common cause of upload issues.

Try the following steps in order:

1. If the upload sticks at 0% or you see "Thumbnail generation failed," re-encode the video to H.264 (MP4, H.264 video, AAC audio) using a free tool like HandBrake or QuickTime, then upload again. This resolves most stuck uploads.
2. If re-encoding doesn't help, rule out your browser and network. Try posting from an incognito/private window, disable ad blockers and browser extensions, turn off any VPN, and try a different network. Learn how to open Buffer in an incognito window, safelist Buffer, and check your VPN.
3. If you're on a work computer or network, check whether antivirus or security software (for example, Bitdefender), a corporate firewall or proxy, or a virtual desktop is blocking the upload. Try a personal device or network to confirm. A full device restart can also clear the "Upload stalled for 60 seconds, aborting" error.
4. If it works in the mobile app but not on the web (or the reverse), that points to a browser or network issue on the device that's failing, not your file. Use the device that works, or apply the browser and network steps above.
5. If it still won't upload, try a small test video (a few seconds of H.264) to confirm the account and connection are fine.

Video size, length, and aspect ratio by network

A video can meet the file size and codec requirements and still be rejected because of its length or aspect ratio. These limits are set by each social network’s API, so they apply to all scheduling tools, not just Buffer.

Aspect ratio, which refers to the shape of the video or image, is a common cause of rejection:

• Instagram supports aspect ratios from 4:5 to 1.91:1 for automatic publishing. Although Instagram’s grid now displays posts in a 3:4 format, its API does not yet accept 3:4 uploads. To avoid a failed post, crop 3:4 media to 4:5 before scheduling. See Instagram's accepted aspect ratio ranges.
• Reels (Instagram and Facebook) need a vertical 9:16 video. Videos that do not use this exact aspect ratio will be rejected.
• YouTube Shorts require an exact 1:1 or 9:16 aspect ratio, such as 1080 × 1080 or 1080 × 1920. YouTube’s API is stricter than its native uploader, so a slightly different size, such as 1078 × 1920, may upload directly to YouTube but still be rejected when published through Buffer.
• LinkedIn accepts video aspect ratios from 9:16 (tallest) to 16:9 (widest).
• Pinterest supports 1:1 square videos (which is recommended), as well as vertical videos in 2:3, 4:5, or 9:16 aspect ratios.

Learn more about the requirements per social network in Sharing your videos through Buffer.

Custom thumbnails, cover images, and video titles

You cannot upload a separate image as a video thumbnail or cover in Buffer. On networks that support thumbnail selection, you can only choose a frame from the video itself.

Choosing a video thumbnail:

• Instagram, TikTok, and Pinterest: After uploading the video, select Edit Thumbnail in the composer to choose a frame from the video.
• Facebook, LinkedIn, YouTube, Mastodon, and Bluesky: Custom thumbnail selection is not supported. These networks automatically choose the thumbnail, and this can't be overridden by any tool.

If you need a specific cover image, try one of these workarounds:

• Add the image as the first frame of the video before uploading, then select that frame using Edit Thumbnail.
• For Instagram and TikTok, use notification publishing, and manually add a video cover in the Instagram or TikTok apps when completing the post.

Video titles are displayed differently depending on the social network:

• Facebook: The title appears at the top of the video post.
• X/Twitter: The title is used when the video exceeds X/Twitter’s file size limits and is displayed as a link to Buffer’s video player instead of a native video.
• Pinterest: The title appears at the bottom of the video in the feed.

Notification publishing, automatic publishing, and "Sent but not live"

If a video appears not to publish, it may be set to notification publishing rather than having failed. Understanding the two publishing modes clears up a lot of confusion:

• Automatic publishing: Buffer publishes the video for you at the scheduled time.
• Notification publishing: At the scheduled time, Buffer sends a notification to the Buffer mobile app. You then complete the post manually in the social network’s app. If you do not complete the final steps in the app, the video will not be published.

To check which publishing method a post uses, open it in Buffer and review the publishing setting. To switch to automatic publishing, open the post in the composer and select Automatic (where supported by the social network and post format).

Why does my video quality look lower after publishing through Buffer?

When you publish a video through Buffer, it may undergo transcoding that can reduce quality, especially on networks like TikTok that support higher resolutions than our current default. There is no setting to turn transcoding off, so the goal is to upload a file that doesn't trigger it, and to expect some additional compression from the network itself.

Your video will be transcoded if it meets any of the following conditions:

• It uses HEVC (H.265) compression
• Its video bitrate is above 25 Mbps
• Its audio bitrate is above 128 kbps
• Its audio uses one of these formats: AAC LC SBR, AAC LC SBR PS, ALAC (Apple Lossless), or PCM (uncompressed)
• The video resolution is larger than 1080p (i.e., more than 1920px on its longest side)
• It was uploaded via a mobile app (all mobile uploads are always transcoded)

Posting videos through the API, Zapier, Make, or n8n

When publishing videos through Buffer’s API or an automation tool such as Zapier, Make, n8n, or a custom script, media requirements are stricter than when uploading manually. This can lead to a specific set of upload and publishing failures.

• Media must remain publicly accessible until the post publishes. Buffer fetches the video from the URL you provide at publish time. If the URL expires, requires a login, or blocks external access, the post will fail. This can happen with Google Drive or Dropbox share links, or with CDNs that use hotlink protection.
• The error “Buffer API Error: #1030: Buffer could not fetch the image [URL]” means Buffer’s servers could not access the media URL. Confirm the URL opens in a private browser window, and that your CDN, firewall, or WordPress host (for example, Cloudflare hotlink protection) allows Buffer to fetch it.
• Custom video thumbnails are not supported through the API. Although the API accepts a thumbnail URL in the payload, Buffer does not apply it when publishing.
• We don't re-host media submitted through the API. The file remains on your server, so the source URL must stay active and publicly accessible until publishing is complete.

Learn more about Using Buffer's API and Using Zapier with Buffer.

Platform limits and what isn't supported

Some video features are limited by each social network's API, not by Buffer, so they can't be changed from our side. Understanding these limitations upfront can help you avoid unnecessary troubleshooting:

• X/Twitter: videos are capped at about 140 seconds for third-party tools, including Buffer. This applies even to X Premium accounts; the longer-video limit only applies when you post directly on X.
• YouTube: Buffer supports Shorts (vertical, up to ~3 minutes), not long-form or landscape YouTube videos. New or unverified YouTube accounts also have a daily upload limit set by YouTube.
• TikTok: every post must include actual media; a link-only post fails. Video frame rate must be within TikTok's supported range (about 23–60fps), and a video that TikTok can't process may fail with a "file format" or "media not ready" error, cleared by recreating the post.
• Bluesky: Videos published through Buffer must be 100 MB or smaller. Bluesky’s native app accepts larger files, but its API does not yet make that higher limit available to third-party tools.
• Facebook: Publishing many videos in a short period can trigger Facebook’s rate limits or spam protection. This often appears as a generic or “unknown” error. Space out your posts and wait up to 24 hours before trying again.
• Google Business Profile: video isn't supported. Google's API allows one image per post through third-party tools, so we're not able to publish video there.
• One media type per post: a single post can contain images or a single video, not both mixed together, even where a network supports mixed media natively.

If a limit is blocking something you need, let us know by submitting a feature suggestion.

Helpful tools for optimizing video files

Smaller, well-formatted videos upload faster and are more likely to post without issues. Need to resize, convert, or compress your video (for example, to change HEVC to H.264)? These tools can help:

• HandBrake – Free desktop app for compressing and converting videos to H.264.
• Clideo – Quick online compressor to reduce file size.
• VEED.io and Kapwing – Easy editors for trimming, resizing, or formatting for social media.

Quick checklist

• ✅ Use MP4 with the H.264 codec (re-encode HEVC/H.265 from iPhone or Mac)
• ✅ Stay within the size, length, and aspect-ratio limits for each network
• ✅ Keep video bitrate under 25 Mbps and audio bitrate under 192 kbps (AAC)
• ✅ Avoid VPNs, ad blockers, and check for antivirus or firewall interference while uploading
• ✅ Check for browser conflicts (try incognito mode)
• ✅ Upload from the web app (not mobile) for the best quality
• ✅ Try a test upload with a small video
• ✅ Review how each network handles videos