Mass Email - failed delivery notification not working !

Mass Email - failed delivery notification not working !

Hi Zoho Support team,

I have 2 installations in Zoho. One is a 5-user Old Professional and another is 1-user New Professional (just installed 2 days back). I will be slowly migrating all 5 users from Old Professional to New Professional once I have worked out and understood all the features of the New Professional version.

I have over 10000 leads in my database (accumulated over 16 years of business). I think over 50% of those emails are working. Others are not. When I send emails using the Mass email feature (50 at a time), it tells me that ALL messages have been successfully sent out. Of course they are sent but MAJORITY of them are not reaching (because of wrong email / domain).

When I use INDIVIDUAL email to send email, I immediately get a notification if the email address that I sent to was wrong (failure / non delivery / non existing email / etc). And then I go about amending the database (finding alternative email by calling / faxing the lead). It is clearly more time consuming to send INDIVIDUAL emails than Mass Email. But it helps me identify the wrong email addresses.

My question is for Mass Email, is it possible to ENABLE notification of NON DELIVERY of messages ??? Right now, I am getting no returns and no non-delivery messages (which is DEFINITELY wrong).

This will really help reduce my workload as I can manage the contacts / leads in my database more efficiently 

Anyone know how to fix this. Zoho Support please help.