SFTP Error: Username/Password Fail

I am trying to use the SFTP setting in Dreamweaver CC 2017. I have all the credentials correct, but I get a username/password failure. I have used the same credentials through another FTP program and can successfully connect, so I know my key file, username, and password are all accurate.

I have entered in my username and password several times to ensure I haven't done so incorrectly, but I still get an invalid username/password prompt.

Any idea what the problem may be? Again, I have re-entered my information and re-linked to the key several times.