When you click a link to a Mastodon post from another instance, the browser may show a “Not Found” error instead of the post content. This happens because the post exists on a remote server, but your local instance cannot find or access it. The cause is often an incomplete federation handshake, a deleted or private post, or a misconfigured instance. This article explains why the error appears and provides step-by-step methods to view the post or understand why it is unavailable.
Key Takeaways: Fixing ‘Not Found’ on Federated Post URLs
- Search by post ID on the remote instance: Use the remote server’s search function with the full post URL to retrieve the post directly.
- Check the post’s visibility settings: The post may be set to followers-only or direct, which hides it from federated timelines.
- Use the remote instance’s public view: Append
/publicor/@username/postidto the remote instance URL to bypass local cache.
Why Mastodon Shows ‘Not Found’ for a Federated Post URL
Mastodon instances communicate through the ActivityPub protocol. When you view a post from another instance, your local instance fetches and caches the post data. The “Not Found” error appears when your instance cannot retrieve the post from the remote server. Several scenarios cause this:
The remote post may have been deleted by its author or a moderator. Mastodon does not store deleted posts in its cache, so the link becomes invalid. Private posts — those marked as followers-only, mentioned-only, or direct — are not visible to users who do not follow the author. If you are not logged into an account that follows the author, the post appears as “Not Found.”
Another common cause is incomplete federation. Some instances block or throttle requests from unknown servers. If your instance has not yet received the post through federation — for example, if the post was created after your instance last pulled updates — the local cache will not have it. The remote server may also be temporarily down or rate-limiting requests.
Finally, the URL itself may be malformed. Mastodon post URLs follow the pattern https://instance.social/@username/postid. If the username or post ID is wrong, the server cannot resolve the post.
Steps to View a Federated Post That Shows ‘Not Found’
- Verify the post URL format
Check that the URL matches the patternhttps://instance.social/@username/postid. The post ID is a string of numbers and letters. If the URL contains extra characters or a different path structure, correct it. For example, a valid URL looks likehttps://mastodon.social/@user/109876543210987654. - Search for the post on your local instance
Log into your Mastodon account. Open the search bar and paste the full post URL. Press Enter. If the post has been federated to your instance, it will appear in the search results. If it does not appear, proceed to the next step. - Search for the post on the remote instance
Open a new browser tab and navigate to the remote instance’s homepage — the part of the URL before/@username/postid. Log into an account on that instance if you have one. Paste the full post URL into the search bar of that instance. This forces the remote server to look up the post in its own database. If the post exists, it will display. If it still shows “Not Found,” the post has been deleted or is private. - Use the remote instance’s public timeline view
If the post was recent, you can find it by browsing the remote instance’s public timeline. Go tohttps://instance.social/public/localorhttps://instance.social/public. Scroll through recent posts to locate the one you need. This method works only for public posts. - Check the post’s visibility via the author’s profile
Visit the remote author’s profile athttps://instance.social/@username. If the post is public, it will appear in the profile’s post list. If the post is followers-only or direct, it will not appear unless you follow the author from an account on the same instance. - Request federation from a different instance
If your instance cannot fetch the post, try viewing it from another Mastodon instance. Create a temporary account on a large instance such as mastodon.social or mastodon.online. Search for the post URL from that account. If the post appears, the issue is specific to your original instance’s federation or cache. - Force a cache refresh on your instance
Some instances allow administrators to clear the cache for a specific remote resource. If you are an admin, runtootctl cache clearon the server. This removes all cached remote objects and forces a fresh fetch. For regular users, ask your instance admin to perform this step.
If Mastodon Still Shows ‘Not Found’ After the Main Fix
Post was deleted by the author or moderator
If the post no longer exists on the remote server, no method can retrieve it. The original author may have deleted it, or a moderator removed it for policy violations. In this case, the only option is to ask the author directly for a summary or screenshot.
Post is private and you do not follow the author
Posts marked as followers-only, mentioned-only, or direct are not visible to users who do not follow the author on the same instance. To view the post, you must follow the author from an account on the same instance where the post was created. If you cannot follow them, the post remains inaccessible.
Remote instance is blocking your instance
Some instances block or limit federation with other instances due to policy or spam concerns. If your instance is blocked, your local server cannot fetch any data from the remote instance. Use the search method on a different, unblocked instance to view the post.
Post URL contains a typo
A single wrong character in the username or post ID causes the “Not Found” error. Double-check the URL against the original source. If the post was shared in a message, ask the sender to resend the exact link.
| Item | Post Exists and Public | Post Deleted or Private |
|---|---|---|
| Search on your instance | Post appears in results | No result or “Not Found” |
| Search on remote instance | Post displays | “Not Found” or login required |
| View author’s profile | Post visible in timeline | Post absent |
| Use public timeline | Post may appear if recent | Post never appears |
This table summarizes the outcomes of each method depending on whether the post exists and is public. If the post is public and exists, at least one method will work. If it is deleted or private, no method will retrieve it.
You can now diagnose and resolve the “Not Found” error on federated Mastodon post URLs. Start by verifying the URL format and searching on your local instance. If that fails, search directly on the remote instance. If the post is private or deleted, you will need to contact the author or use an alternative source. For future reference, bookmark the remote instance’s public timeline or follow the author on the same instance to avoid this error. As an advanced tip, use the Mastodon API endpoint /api/v1/statuses/:id with the post ID to fetch raw post data directly from the remote instance.