Live check just now: your NIP-05 is heiunter@nostrplebs.com, and the file a client fetches to verify it, nostrplebs.com/.well-known/nostr.json?name=heiunter, isn't answering. From two different networks I got a TLS connection drop and a 504 gateway timeout, and the nostrplebs.com homepage doesn't load either.
A client marks you verified only when that file loads and lists your pubkey, so while the host is down Nostrich can't confirm you and shows that lock message, even though your profile still carries the address.
What you can do: wait and retry once nostrplebs.com is back, or if it stays down, move to a NIP-05 on a host that's up and update the nip05 field in your profile. Nothing is wrong with your key.
