When you try to post an image on Bluesky and see a “Server Error” message, the image upload fails and the post does not appear in your feed. This error typically occurs due to a temporary outage on Bluesky’s image processing servers, a corrupted image file, or a network issue that blocks the upload endpoint. This article explains the most common reasons for the error and provides a clear sequence of diagnostic steps to identify and resolve the problem.
Key Takeaways: Diagnosing Bluesky Image Upload Errors
- Bluesky Status Page (status.bsky.app): Check this page first to see if image uploads are reported as degraded or down.
- Clear browser cache and cookies: Removes corrupted session data that can trigger upload errors.
- Convert image to PNG or JPEG under 1 MB: Large or unsupported file types are a common cause of server-side rejection.
Why Bluesky Returns a Server Error When Uploading Images
Bluesky uses a separate media processing service to handle image uploads. When you attach an image, the app sends the file to a dedicated server that resizes the image, generates thumbnails, and then attaches the processed file to your post. A “Server Error” means that this media processing server either could not receive the file or could not complete the processing step.
The root cause falls into one of three categories:
1. Bluesky’s Media Infrastructure Is Unavailable
The most frequent cause is a temporary outage or high load on Bluesky’s image processing servers. When the media service is down, all image uploads fail regardless of your internet connection or device. This is usually resolved within minutes to hours by Bluesky’s engineering team.
2. Local Network or DNS Interference
Your internet service provider, corporate firewall, or DNS resolver may block the specific domain used for image uploads. Bluesky uploads go to a subdomain like cdn.bsky.app or media.bsky.app. If your network blocks or throttles these domains, the upload request times out and returns a server error.
3. Corrupted or Unsupported Image File
Bluesky expects images in JPEG, PNG, GIF, or WebP format, with a maximum file size of 1 MB per image. Files that exceed this size, have a corrupted header, or use an unsupported color profile can be rejected by the processing server. The client app may still show the image preview, but the server refuses to process it.
Diagnostic Steps to Identify and Fix the Server Error
Follow these steps in order. Test after each step by posting an image. Stop when the image posts successfully.
- Check Bluesky’s official status page
Open a browser and go to status.bsky.app. Look for any reported incident under “Media Upload” or “Image Processing.” If a status indicator shows a red or yellow dot, the problem is on Bluesky’s side. Wait for the status to change to green before continuing. - Test with a text-only post
Create a new post with no image and publish it. If the text post succeeds, the problem is specific to image uploads. If the text post also fails, the issue is with your account authentication or a general Bluesky outage. - Switch to a different network
Disconnect from your current Wi-Fi and use your mobile phone’s cellular hotspot. Alternatively, try posting from a public Wi-Fi network at a coffee shop or library. If the image upload succeeds on a different network, your home or office network is blocking the media upload domain. - Clear browser cache and cookies
In your browser, go to Settings > Privacy and Security > Clear browsing data. Select “Cookies and other site data” and “Cached images and files.” Set the time range to “All time.” Click Clear data. Then restart the browser and try posting the image again. - Use a different browser or device
Install Bluesky’s official mobile app on your phone, or try a different desktop browser like Firefox or Edge. If the image upload works in the alternative app, the original browser has a corrupted extension or service worker that interferes with uploads. - Convert the image to a supported format and size
Open the image in an image editor like Paint or Photoshop. Resize the image so the shorter side is 2000 pixels or smaller. Save it as JPEG with quality set to 80 percent. Check that the file size is under 1 MB. Upload the converted file. - Restart your modem and router
Unplug your modem and router from power. Wait 60 seconds. Plug the modem back in and wait for all lights to stabilize. Plug the router back in. After the network reconnects, try the image upload again. - Flush your DNS cache
Open a command prompt as administrator. Type ipconfig /flushdns and press Enter. You should see the message “Successfully flushed the DNS Resolver Cache.” Then type ipconfig /renew and press Enter. Wait for the command to complete. Try posting the image.
If Bluesky Still Returns a Server Error After These Steps
“Server Error” appears only on the web app but not the mobile app
This indicates a browser-specific problem. Disable all extensions, especially ad blockers or script blockers. Open the browser’s Developer Tools (F12) and go to the Console tab. Look for red error messages that mention “blob:” or “fetch.” If you see a CORS error, the browser is blocking the upload request. Try using a private or incognito window.
“Server Error” appears only for one specific image
The image file itself is likely corrupted. Open the image in an image editor and re-save it as a new file. Do not use “Save” — use “Save As” and choose a different file name. If the error persists, the image contains metadata that Bluesky’s server rejects. Use an EXIF removal tool to strip all metadata before uploading.
“Server Error” appears for all posts after a recent account change
If you recently changed your Bluesky handle, email address, or password, the authentication token stored in your browser may be out of sync. Log out of Bluesky completely. Clear all site data for bsky.app in your browser settings. Log back in and try posting an image.
| Diagnostic Step | What It Tests | Expected Outcome |
|---|---|---|
| Check status.bsky.app | Bluesky server status | Green indicator means servers are healthy |
| Text-only post test | Account and general connectivity | Text post publishes without error |
| Network switch test | Local network or DNS block | Image uploads succeed on alternate network |
| Image format conversion | File corruption or size limit | Converted JPEG under 1 MB uploads |
| DNS flush and router restart | DNS resolution and routing | Upload succeeds after network reset |
You can now systematically diagnose a Bluesky “Server Error” when posting images by checking the status page, testing on another network, converting the image file, and flushing your DNS cache. If the error persists after all eight steps, submit a support ticket through Bluesky’s help center with the exact error message and the diagnostic results. For frequent uploaders, bookmark the Bluesky status page and keep a saved copy of your images in JPEG format under 1 MB to avoid future upload failures.