Thanks
I think disabling recordings is not a solution if you do actually want them included in your backup. You should be able to get them to work.
Sounds like your FTP times-out while the backup is being prepared and transferred. I used filezilla as my ftp server, set timeout to 0 and had no issue with a 7GB file. If i leave the default timeouts, I get the same error as you, indicating that the FTP session ends prematurely and the pbx cannot continue. Your FTP server should be ok once you find a way to increase the session timer.