The error caused by file “known_hosts” in your local machine.
File “known_hosts” store a key authenticating when you connect to VPS using ssh/sftp. The key will be generated in your local machine and VPS.
If key matched, you can access it. If not, you can get error like image above.
Let’s fixing it !
1) Open /home/user (ctrl + h to show hidden file)
2. Open folder .ssh and then you can see file “known_hosts”. Change it to “known_hosts.old”
3. Try again to connect by sftp. File > Connect to Server and input your sftp location. If you get notification like image below, you can access your VPS. bingo! 🙂