Sending Confirmation Email Suddenly Stopped

Hi All,
I have been using PHPList script for over 2 years now and never had problem with it. I love this program and honestly I haven't seen any other script more powerful and organized than this one until now.
I just now realized when a user subscribe to any of our list no Confirmation Email is being sent to them. I checked the different users history and found out this function even was working until 3 months ago but now only notification emails are not going anywhere. Here is the summary of the problem:
- Sending email is working perfect (I'm sending thousands of emails every week using PHPList)
- No error is displaying at subscription page.
- In configuration I have define("PHPMAILER",0);
- Even re-sending notification is not working and not error message is displaying.
- As our server support guy says we had no change whatsoever in any services lately.
Has anyone had such problem before?
I have been searching for a similar problem everywhere but no success as of yet. I highly appreciate if you guys have any idea or solution to share with me.
Thanks,
Ben
I have been using PHPList script for over 2 years now and never had problem with it. I love this program and honestly I haven't seen any other script more powerful and organized than this one until now.
I just now realized when a user subscribe to any of our list no Confirmation Email is being sent to them. I checked the different users history and found out this function even was working until 3 months ago but now only notification emails are not going anywhere. Here is the summary of the problem:
- Sending email is working perfect (I'm sending thousands of emails every week using PHPList)
- No error is displaying at subscription page.
- In configuration I have define("PHPMAILER",0);
- Even re-sending notification is not working and not error message is displaying.
- As our server support guy says we had no change whatsoever in any services lately.
Has anyone had such problem before?
I have been searching for a similar problem everywhere but no success as of yet. I highly appreciate if you guys have any idea or solution to share with me.

Thanks,
Ben