Sendmail sending blank emails.

["kumarlimbu" <user=1589@nabble.blu.org>]

 Hi everyone, 

We have setup sendmail on a linux box as our SMTP server. This server is responsible for sending emails to users whenever anyone register. These emails will be used for validation purposes. 

What we have found during the course of time is that around 30% of new users do not validate their email, which we feel is quite high. We have also received complaints from users who say that they received blank messages on their validation email. 

Whenever I am testing the app, I have never encountered any problem in creating an account and validating. Has anyone encountered similar issues with blank email being sent? Does anyone have any suggestions where we should look to begin troubleshooting this problem? 

Thank you for your time.