The phrase “couldn’t talk” on Snapchat typically appears when you’re trying to add someone using their username and you get a message saying "Sorry! Couldn’t find username"1. This could mean that the person has blocked you or that the username you entered doesn’t exist1. If you’re having trouble sending chats, it could be due to several issues such as needing to update Snapchat, poor internet connection, or needing to close and reopen the app2.