There are several reasons why you may be receiving a lot of bounce backs. For example:


1. Your host has placed a limit on the number of emails you are allowed to send per hour


When this limit is in place, the server automatically bounces back to your domain all the emails over the limit. The only way to find out your hourly sending limit is to ask your web host.

If they say, for example, 500 per hour, make sure that the email system you are using is set to comply to that limit:


http://support.arpreach.com/support/solutions/articles/76170

2. Your emails are getting “off” your server, but bouncing at the ISP


There are a number of reasons why your emails may be blocked by providers (like Outlook.com, Gmail, AOL, etc.). It may be due to:


• Your IP address being blocked

• The content in your messages being blocked

• A URL in your messages is on a blacklist

• You sending messages to non-existent email addresses


To determine why your messages are bouncing back, and so you and/or your web host would have an idea on how to correct it, you need to read the headers in the bounce messages. To review the actual bounce messages, your may refer to this article:


http://support.arpreach.com/support/solutions/articles/4000170277