SQL Server Backups are not moving to FTP server

Hi,

Daily we are moving SQL backups from SQL server to FTP server with schedule plan with the use of Task Scheduler.

previously it was working fine but since last 1-month backup files are not moving with data to FTP server. only backup files names are moving with 0 KB.

Can you please suggest me what changes do I need to do in SQL server or FTP server.

Thanks in Advance.