The SMTP mailsender is not logging any info into the debuglog file, if you want to see the logging then you will need a tool called DBGVIEW. You can download this from http://beta.woodstone.nu/soft/support/debugview.zip
Run that next to Servers Alive and check the logging.
If you're running Servers Alive on a system that has more then one IP address, then make sure to update to Servers Alive v6.1.