You may receive the error 550 No connections allowed from your IP when you have connected to an FTP server using the incorrect credentials too many times.
As a result of the number of failed login attempts, the FTP server prevents any further connections from your IP.
To resolve this, reset your FTP password from within SolidCP, update your ftp application credentials and try again after 1 hour.
Unfortunately, support cannot restart FTP services to resolve the issue as this affects all clients within the shared hosting environment.