When you try to follow a hashtag in Mastodon, you may see the error message “Could not find hashtag.” This happens even when the hashtag exists and is actively used on the instance. The error prevents you from subscribing to updates for that topic, which breaks a core feature of the platform. This article explains why the error occurs and provides a step-by-step fix to resolve it.
Key Takeaways: Fixing the “Could Not Find Hashtag” Error in Mastodon
- Search bar > Enter hashtag name: Type the hashtag in the search box and select it from the dropdown to confirm it exists on your instance.
- Hashtag page > Follow button: Navigate to the hashtag page directly and click the Follow button there instead of using the search results.
- Preferences > Appearance > Enable advanced web interface: Turn on the advanced interface to access hashtag columns that bypass the follow error.
Why Mastodon Shows “Could Not Find Hashtag” When You Try to Follow It
The “Could not find hashtag” error occurs because Mastodon’s search index does not immediately recognize a hashtag as a followable object. When you click the Follow button on a hashtag in search results, the system tries to locate the hashtag in its local database. If the hashtag has not been indexed yet — either because it is new, rarely used, or your instance has not cached it — the server cannot create a follow relationship.
Mastodon treats hashtags as first-class followable entities only after they appear in a post that your instance has processed. The follow action requires a valid hashtag ID in the database. When the ID is missing, the error appears. This is not a bug in most cases but a limitation of how Mastodon’s search and federation handle hashtags.
Another reason is that the hashtag may exist on a remote instance but not on your home instance. Mastodon does not federate hashtag objects by themselves. A hashtag only appears on your instance when a post containing that hashtag is federated to your server. If no one on your instance has posted with that hashtag, or if the remote post has not arrived yet, the hashtag remains invisible to the follow system.
Steps to Fix the “Could Not Find Hashtag” Error in Mastodon
Use the methods below in order. Start with Method 1 because it is the fastest fix. Move to Method 2 if the error persists. Method 3 is a permanent workaround for users who follow many hashtags.
Method 1: Force the Hashtag to Appear by Searching and Selecting It
- Open the Mastodon search bar
Click the search icon in the left sidebar or press the / key on your keyboard. The search box appears at the top of the screen. - Type the exact hashtag name including the # symbol
For example, type #Mastodon or #TechNews. Do not add spaces. A dropdown list appears with matching results as you type. - Click the hashtag result in the dropdown
Do not press Enter. Click the hashtag entry that appears under the search bar. This navigates you to the hashtag page. - Click the Follow button on the hashtag page
On the hashtag page, you see a Follow button near the top. Click it. The button changes to Unfollow, confirming the follow is successful.
This method works because the hashtag page loads the full hashtag object from the server, including its database ID. The search dropdown also triggers a lookup that creates the hashtag entry if it was missing.
Method 2: Post a Message with the Hashtag First
- Create a new post
Click the Compose button in the left sidebar. The compose window opens. - Type the hashtag in the post body
Write a short message and include the hashtag. For example: “Testing the #Mastodon hashtag follow feature.” - Publish the post
Click the Publish button. The post appears on your timeline and the hashtag is now indexed on your instance. - Navigate to the hashtag page and follow it
Click the hashtag in your post to go to its page. Then click the Follow button as described in Method 1.
Posting the hashtag forces your instance to create a local record of it. After that, the follow action works immediately. This is the most reliable method for hashtags that are not yet indexed.
Method 3: Use the Advanced Web Interface with a Hashtag Column
- Enable the advanced web interface
Go to Preferences > Appearance. Check the box labeled “Enable advanced web interface.” Save the change. - Reload Mastodon
Refresh the page in your browser. The interface now shows multiple columns instead of a single timeline. - Add a hashtag column
Click the + icon in the column area. Select “Hashtag” from the list. Enter the hashtag name without the # symbol. Click Add Column. - Pin the column
Click the pin icon in the column header. The column now shows all posts with that hashtag and updates in real time. This bypasses the follow system entirely.
The advanced web interface does not require following the hashtag. The column acts as a live feed. This is useful for hashtags that repeatedly fail to follow.
If the Mastodon Error Still Appears After the Main Fixes
Hashtag Does Not Appear in Search at All
If the hashtag does not show up in search even after you post with it, the issue may be with your instance’s search settings. Mastodon instances can disable full-text search. Go to Preferences > Other and check if “Allow search indexing” is enabled. If it is off, the search index does not include hashtags. Turn it on and wait a few minutes for the index to rebuild.
Following the Hashtag Works Temporarily Then Breaks
This happens when your instance purges old data. Mastodon administrators can set a retention period for posts and hashtags. If the hashtag has no new posts for a long time, the server removes its record. You then see the error again. To avoid this, pin the hashtag column in the advanced web interface instead of following it.
Error Appears Only on Mobile Apps
Some third-party Mastodon apps handle hashtag following differently. If the error only shows on your mobile app, try following the hashtag from the web interface first. The follow relationship syncs to the app after a few seconds. If it does not, log out of the app and log in again.
Mastodon Hashtag Follow vs Column Pin: Key Differences
| Item | Hashtag Follow | Column Pin (Advanced Interface) |
|---|---|---|
| Setup method | Click Follow on hashtag page | Add column via + icon |
| Shows in timeline | Posts appear in Home timeline | Posts appear in separate column |
| Requires hashtag index | Yes, hashtag must exist in database | No, column works with search query |
| Persistence | Lost if instance purges hashtag data | Column persists until you remove it |
| Mobile app support | Works on most apps | Only in advanced web interface |
Choosing between these two methods depends on your use case. If you want hashtag posts mixed into your Home feed, use the follow method. If you prefer a dedicated live feed that never breaks, use the column pin in the advanced web interface.
You now know how to fix the “Could not find hashtag” error in Mastodon by forcing the hashtag to appear in search, posting the hashtag yourself, or using the advanced web interface column. Start with Method 1 because it is the fastest. If the error persists, use Method 2 and post the hashtag first. For hashtags you follow long-term, enable the advanced web interface and add a pinned column. This approach avoids the error entirely and gives you a stable feed for any hashtag.