What version of ASG are you running?
Also, do you host your own mail server inside your network? or are you POP-ing from an ISP's mail server?
Using the latest 7.101.
sending Backups worked until update 7.0 to 7.1
Im using my own internal mailserver but I ve no idea where to find the configuarion for the mailserver (system and login) to check I ve there is soemthing wrong now.