@simon

"I enter "user@brandnewserver.net", search says "I don't know about that user, but let me reach out to brandnewserver.net and see if the user exists", "

If you're entering the full account address, that's exactly what it does do. Even if your server has never heard of the other server, it forces your server to contact the other server straight away and check for such a user.

Do you mean searching for a partial account address?

@simon

If your instance is configured correctly and federating, it should work with any valid account address ( @ user @ example.com ) as long as you haven't defederated that account's instance.

Usually it should work on the first go with a slight delay, but sometimes it takes a few repeated attempts.

It also works with the web address of the account, I'm not sure why your instance would be working with one address format but not the other?

Yeah, I can't speak on behalf of every client 🙂

The web client is maybe the best reference point for testing Mastodon features as it supports (almost) all of them. If it isn't working at all in the web client then there may be a configuration issue.

Having said that, sometimes it won't work at all if the other instance isn't responding. Some instances are very slow or go down often, and these may not respond to requests for accounts. In such cases you have to try again later.