FTP
530 Not Logged In
Not logged in. The user is not authenticated and must log in before the requested command can be executed.
이 코드를 보게 되는 경우
When you try to access files or run commands before authenticating, or after providing incorrect login credentials.
해결 방법
Send USER and PASS commands with valid credentials. If login fails repeatedly, verify the username, password, and check if the account is locked.