42N3 on Nostr: These IDs are according to https://github.com/nostr-protocol/nips/blob/master/05.md ...

These IDs are according to https://github.com/nostr-protocol/nips/blob/master/05.md (NIP-05). A Nostr client that sees either silner@aapl.pro or silneratnostr@iris.to may (may, not must or will!) request https://aapl.pro/.well-known/nostr.json?name=silner or https://iris.to/.well-known/nostr.json?name=silneratnostr to get your public key. Both servers respond with the same public key, your nostr identity:

Silner (npub12a5…s64l)

What any client will display for that depends from which client you published your profile the last time. I see "Silner". Consequently I can tag you with "@Silner" but not "@silneratnostr" - even if I append the domain.

I would recommend to switch to one of the two variants on all clients, just edit your profile to match the other clients one!