Mastodon Migration Lost Followers Due to Defederation: Recovery

You moved your Mastodon account to a new instance and expected all your followers to transfer automatically. Instead, many of them disappeared from your new account list. This happens because follower migration depends on the old instance sending a handshake request to each follower’s server. If that server has defederated from your old instance, the request is blocked and the follower transfer fails. This article explains why defederation causes follower loss during migration and provides step-by-step methods to recover those lost connections.

Why Defederation Prevents Follower Migration Between Instances

Mastodon’s account migration feature works through a two-step handshake. When you start a move from your old account, the old instance sends a Move activity to every server that hosts one of your followers. That server then updates its local database: it unfollows your old account and follows your new account. This process requires direct communication between the old instance and each follower’s server.

Defederation breaks this communication. If a follower’s instance has blocked your old instance, it will not accept any incoming activities from that server. The Move request is silently dropped or rejected. Your old instance never receives an error message, so it assumes the transfer succeeded. Your follower count on the new account remains incomplete.

The defederation can be one-way or mutual. A one-way block means the follower’s instance refuses connections from your old instance. Mutual defederation means both instances have blocked each other. In either case, the handshake fails for all followers on the blocking server. No automated recovery is possible because the old instance cannot reach the follower’s server at all.

How to Identify If Defederation Caused the Loss

Check the follower’s instance by looking at the domain of the missing follower. For example, if a follower’s profile shows @user@example.social, the instance is example.social. Open your old instance’s moderation page at https://oldinstance.com/admin/instances and search for that domain. If the status shows Blocked or Suspended, defederation is the cause. You can also ask the follower to check their instance’s federation page for your old instance’s domain. If it shows Blocked, the same condition applies.

Steps to Recover Followers Lost Due to Defederation

Method 1: Ask Followers to Manually Follow Your New Account

This is the most reliable recovery method. The follower’s instance can still reach your new instance because the block only applies to your old server. You must reach the follower outside of Mastodon or through a mutual connection.

1. Identify the missing followers
   Open your old account’s profile page on the old instance. Scroll through your follower list. Note the usernames and instance domains of followers who did not appear on your new account. Cross-reference with your new account’s follower list.
2. Contact each follower directly
   Use a platform you both have access to, such as a shared Discord server, a group chat, or email. Ask them to visit your new profile URL, for example https://newinstance.com/@yourusername. Tell them to click the Follow button on that page.
3. Ask the follower to verify the follow
   After they follow, they should see your posts in their home timeline. You should see their username appear in your new account’s follower list within a few minutes.
4. Repeat for each affected follower
   This process is manual. There is no bulk re-follow option. Prioritize followers from instances you know have defederated from your old server.

Method 2: Use a Cross-Instance Mention to Trigger Re-Follow

If you cannot contact the follower directly, you can try to reach them through a public post. This method works only if the follower still sees your old account’s posts in their timeline. Defederation does not always remove old posts from the follower’s view immediately. If your old account is still visible, you can send a mention from your new account.

1. Post a public message from your new account
   Write a toot that includes the follower’s full handle, for example @user@example.social. The message should explain that you moved and ask them to follow your new account. Include a direct link to your new profile.
2. Wait for the follower to see the mention
   The mention will appear in their notifications if their instance has not blocked your new instance. If it does appear, they can click the link and follow you.
3. Repeat for each missing follower
   You can include multiple handles in one post, but Mastodon limits mentions to a few per post to avoid spam. Space out the posts over several days.

Method 3: Ask Your New Instance Admin to Request Federation

If many followers are on the same defederated instance, you can ask your new instance admin to contact the other instance admin. This is a long-shot recovery method because it requires both admins to agree to remove the block. It works best when the block was a temporary measure or a misunderstanding.

1. Find the contact information for the follower’s instance
   Look at the instance’s about page, usually at https://example.social/about/more. Find the admin email address or a contact form.
2. Explain the situation to your new instance admin
   Send a direct message or email to your new instance admin. Include the domain of the defederated instance and the number of followers affected. Ask them to initiate a federation request.
3. Wait for the admins to negotiate
   If both admins agree, the block is removed. After removal, you can start a new migration from your old account. This will trigger the Move handshake for all followers on that instance. Your follower count on the new account will update.

If Mastodon Still Shows Missing Followers After Recovery

Followers on Instances That Blocked Your New Instance

If the follower’s instance has defederated from your new instance, they cannot follow you at all. The only solution is to choose a different new instance that is not blocked by the follower’s server. Check the follower’s instance federation page before migrating to verify compatibility. This situation is rare because most defederation lists are short.

Followers Who Were Already Unfollowed Before Migration

Some followers may have unfollowed your old account before you started the migration. The Move handshake only transfers active followers. Check your old account’s follower history to see if any followers left before the migration date. These users must follow you manually again.

Followers on Instances That Are Suspended or Deleted

If the follower’s instance has been suspended by your old instance or has shut down entirely, their account no longer exists. No recovery is possible. Remove these entries from your mental list of lost followers.

Item	Automated Migration	Manual Re-Follow
Description	Uses the Move activity handshake between instances	Follower clicks Follow button on your new profile
Requires defederation check	Fails if old instance is blocked by follower’s server	Succeeds if new instance is not blocked
Time to complete	Minutes after initiation	Days to weeks depending on follower response
Scalability	Transfers all followers at once	Must be done one follower at a time
Failure mode	Silent drop of Move request	Follower never sees the request

You can now recover followers lost during migration due to defederation. Start by identifying which followers are missing and which instances blocked your old server. Use manual re-follow requests for those followers. If many followers are on one blocked instance, ask your new admin to negotiate federation removal. To prevent future loss, check the defederation status of your old instance against follower instances before starting a migration. Use the Mastodon instance federation checker tool at https://fedicheck.com to scan for blocks before you move.