So like, I'm trying to join my friends server (On the computer), and it keeps saying "Login failed" or Error: Failed to connect to server. I've tried restarting minecraft, but it's weird because the server works for everyone else, and it worked fine for me yesterday. If you can, just maybe tell me what I should do to fix it so it works again. Thanks!
Added (1). I tried resetting the router, and it still doesn't work.