If you're @-ing someone on here, it's really important to make sure you've chosen the right person.

Account addresses on Mastodon and the Fediverse always have two parts, the username and the server. Both these parts have to be correct for it to reach the right account.

This is similar to email addresses: you can't just put the first part, you need to include the server at the end too.

To see someone's full account address, look at their profile page. More info at https://fedi.tips/how-to-use-mastodon-and-the-fediverse-basic-tips/#WhatsMyAccountsAddress