- On my Threads profile, I changed my featured link to be my Mastodon profile URL.
- Then, on my Mastodon profile, I changed one of the featured links to be my Threads profile URL.
- After I saved that change, my Mastodon profile showed a green verification checkmark next to my Threads profile URL. Success!
Ask yourself this: why have you come to the Fediverse in the first place?