LinuxQuestions.org - sendmail/mail -> SMTP works through Evolution but not in BackupEDGE or terminal

Hello,

Recently we setup a new Red Had Linux server and which had a purchased and installed copy of BackupEDGE. I went through the steps in the Notifier and Edit Backup Schedule screens to have the system e-mail myself and my boss when a backup runs and completes or fails every morning at 1am. However, I or my boss have never received any notifier e-mails from BackupEdge.
A few days ago I altered the define('SMART_HOST','smtp.mymailserver.net')dnl line in sendmail.mc in /etc/mail to go to my mail server, saved it, Make'd it as it said to do, then used the built-in Evolution mail client, set it to use Sendmail instead of SMTP for sending mail out and was able to successfully send a couple of e-mails from the server through our mail hosting company to my office pc, so it seems like sendmail works, at least in Evolution??

But if I go to a terminal prompt & type "mail myself@mycompany.com" at the terminal prompt, then I put in my subject, then the body of the message, then ctrl-c to end the body and hit enter at the cc: then the Terminal responds "You have mail in /var/spool/mail/root". I opened the text file in that directory and it showed the message I just composed and in the header of it talked about the Final-Recipient being my e-mail address, action: failed, status: 5.1.8, diagnostic-code: smtp; 553 5.1.8 <root@cab.local>...Domain of sender address root@cab.local does not exist
This root file is also where all the logs are going from the BackupEDGE program.
Also, In BackupEDGE, the Command: line in the Notifier screen is set as
|/bin/mail -s %S %n

Is the problem that some portion of mail/sendmail doesn't know my SMTP server address so it can send the e-mail out on it? If so, where do I configure that? Is that information put somewhere in sendmail.mc in /etc/mail or some other file?

thanks in advance,
david