On fileZilla unable to connect FATAL ERROR: Connection union

FileZilla is approximately equal to WinSCP for MAC

In the figure, the host is [FTP, SFTP..] :// Remote IP address, the user password is entered correctly, then the port used a port 80 (already open), the result of a run report error.
Change the port to another port, but still report an error.
Then think of the next, other software transmission is more than 22 port, so change to 22 port (has been opened), connected successfully!
Reason: Unknown

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