Hello Jaswanth Jain, 

The first place to look is your spool. You can 'Right-Click' -> view -> Recipients and see if there are any reported errors. 

If you see an error here you can act on what you find. 

If this does not show you what you are looking for you can grab the EML number from the left column ( the last 5 digits only ) and search the Delivery logs for this number. 

This should show you the full session so far for that particular email. In here you will wan to look for any errors or disconnects. 

If this also fails to provide any data you can just do a search with no terms and start reviewing your log till you see an issue. 

I hope this helps. 

Thank you

Hi

We had already chatted on this and we did find that this is not working as the mails are still showing in Queue, we need your support

Pending 601 Attempted to send the message to the following ip's 

I m getting an error like this

A 601 error is a generic error, and just means that the attempt to send the message failed. To determine the detailed failure information you'll need to go into Manage>View Logs and look up the Delivery logs that relate to the to address that failed delivery. This should return the SMTP session that failed and allow you to see the exact error that caused the 601 error.

14.7 should easily upgrade to the final version of v15 (15.7.6970). 

I still have a client on this version, and it's damned-near bulletproof. Unless you have your SM customized with incompatible 3rd party apps or custom add-ons, might I suggest upgrading?

(as usual, your mileage may vary)