Access Denied when trying to login.

Hello, I haven't used WinSCP in a while and when I did I was a beginner so this is fairly new to me. I am trying to login with the details that was saved for me from the person before who used this. When I put the Host name, Username and Password with the File Protocol SFTP and try to login it shows this message (see attachment); please can someone tell me why this is happening and possibly provide a solution. Thank you.

We cannot tell why you cannot login to your server. You have to talk to your server administrator.

See also:
https://winscp.net/eng/docs/faq_username
https://winscp.net/eng/docs/message_access_denied