High bounce rate after flossing



If you're getting 20-30% bounce rate after using mailfloss something is certainly wrong.

If using an integration

The first thing to check is the aggressiveness setting. Is it on Safe aggressiveness (now deprecated)? If yes, this likely is the reason for a high bounce. Safe is a very cautious setting and only flosses and identifies invalid email addresses if we are absolutely certain the email address is invalid. If you are using a Custom floss setting you may be excluding some crucial tests, as well. Most likely you will want to use the Normal setting or even Aggressive, instead. There is a link in the app beside the "Aggressiveness options" called "help me decide". Click this link to determine the appropriate level of aggressiveness. Read more about the aggressiveness settings here.



The second thing to check is if you have Manual Mode turned on. If you do, have you looked in the integrations page to see if there are any invalid email addresses? These will accumulate in the integrations page if left unattended. If you have Manual Mode turned on, the invalid email addresses are not automatically removed. You will need to visit the integrations tab and manually remove the email addresses yourself.



If using the file upload or copy and paste methods

If you've exported the mailfloss floss report and uploaded the results to your email service provider directly, make sure you are using only email addresses that have passed and not the email addresses that haven't. This is a fairly common mistake as the result report contains both failed and passed addresses. You can read more about the status and category definitions here and here.



Other things to consider

There are many reasons an email address can bounce, and mailfloss helps reduce this by identifying email addresses that are invalid. But an invalid email address is not the only reason an email address bounces. The easiest way to see the reason an email address bounced is to look at the bounce report. The bounce report should have indicators like the bounce message and bounce reason.

Some of the reasons that are not related to invalid email addresses include:

If you'd like us to take a look at the bounce report, please include it in the support ticket.

Most email service providers consider 7-8% or more as a high bounce rate, and when many email service providers will start issuing warnings and banning accounts. We try to get the bounce rate below 5% to keep you in the safe zone, and ideally below 3%. Please note the only way to 100% truly verify an email address is real with the intended recipient on the other end is to have the recipient respond to a sent email and verify that they are real. No service will be able to get that completely right all of the time, but we try our best and are constantly improving our service with new tests and techniques.