There are many reasons why an email may not reach the intended recipient and therefore return to the sender. There is normally an explanation as to why the email could not reach the recipient attached to the bounce back. These will lead to a grouping of such emails in two piles; the soft bounces and hard bounces. There are a few differences between them.
Soft bounces are usually the result of some temporary reason. The recipient's mailbox might have been busy at the time, the domain could be blocked, the mailbox may be full, the account could also be down for the moment, or its limit reached, among other reasons. You can repeat sending for a few more times. If there still is no success, it becomes a hard bounce. Examine the knowledge that we shared about how to reduce email bounce rate
Hard bounces are email messages that are permanently undeliverable. This occurs when you write an invalid address, the mail server has blocked your server, or it has filtered the emails and saw fit to return yours.
Errors codes for these two categories are different, with the soft ones beginning with four, while the hard ones beginning with five. The mail server has different categorization structures for these two types. Your email might be a hard bounce on one, yet a soft bounce on another.
While marketing, you will need to deal with blocked emails, if you re to be successful. You need to keep the number of bounces down, as you reduce the cost of delivery, and get a higher conversion rate at the end of the campaign. Get more information about hard bounce vs soft bounce
You need to check the email addresses you are about to send to for validity. There is email verifier software, which shall aid you in this task. You can also check them manually.
You should also send confirmation emails to the recipient when they subscribe to your list. This will tell you early enough whether the email is valid. To simplify matters, include an email confirmation button on the sign-up page for all new visitors. Learn more details about bounced emails https://en.wikipedia.org/wiki/Bounce_message
You can also allow them to edit their email addresses in your emails. In case they get new ones, they can include them there.
You also need to be updated on all blacklist activities, to ensure your ISP is not among them. If you are blacklisted, you will not know when you have gotten bounced emails.
There is also a spam trap address you need to remove from your list. It is usually what prevents anyone from sending an email. They are there to stop people from sending spam.
You should also do a trial sent to yourself or your friends. You will then know if everything is ok. After that, you can send to everyone on your list of subscribers.