TL;DR:
I’m unable to migrate old accounts to a new instance’s admin account because the account aliases can’t seem to be seen outside the instance. Migrating between old accounts in other instances works fine. Migrating a new account from outside the instance into a new (non-admin) account on the new instance works fine.
Error message:
Handle of the new account is not back-referencing this account
The accounts (letters are for reference use in text below):
[A] @konc@photog.social (old account)
[B] @konc@writing.exchange (old account)
[C] @konc@mastodon.justafellow.com (new account I want to keep)
Since initially posting, I’ve also created these accounts:
[D] @vjeko@mastodon.social
[E] @vjeko@mastodon.justafellow.com
I have created account aliases for accounts [A] and [B] on the third account [C]
When I then try to run the migration (from an old account) it fails. I get the same error from both old accounts.
Handle of the new account is not back-referencing this account
Then, to check if the issue I have is with the feature or my instance, I attempted to migrate account A to account B using the same procedure and it worked just fine, leading me to think that something’s not quite set correctly in my new instance.
I then got the suggestion to create two new accounts, one on another instance instance (account [D]) and one on my instance (account [E]), and I was able to instantly migrate [D] -> [E], and even [E] -> [C].
I’ve also tried to create an account alias from [B] to [C], even though it should’t be needed (and I’ve only ever needed one-way aliases for the migrations that have worked).
I’m hoping that someone else has insights that can help me figure this out.