Unable to send Notification Email because 147

I am just beginning to use CBU, I have a working backup, and now I have added the needed commands to the script to send me an email notification, but I am getting this message at the end of the backup:

18.02.2015 10:39:17 Writing indexation…
18.02.2015 10:39:17 Items backup is complete.
18.02.2015 10:39:17 Closing backup…
18.02.2015 10:39:26 Size compressed is 576 MB, size uncompressed is 576 MB.
18.02.2015 10:39:26 Backup Process Complete
18.02.2015 10:40:27 Unable to send notification email because 147
18.02.2015 10:40:27 Successfully finished

Does anyone have a clue? Any ideas?
If anyone has a script file with working email notification, would you please share?
(Backup version
The parameters that I placed in the email commands are ones that I have used with other products (BLAT specifically) and they work there.