What is an Email Address Blocklist
Email Address Blocklists prevent your email being delivered.
An email address blocklist is a list of senders whos emails should be blocked when being delivered. If you are on a block list some of your emails will not be delivered. Email providers use different block lists and handle them differently, so you may have some emails being blocked but not all.
There are many blocklist providers some work with email servers to automatically list senders that look like spam, others require complaints to be made manually. It might look like spam if you dont warm up your ip address and start to send lots of email.
There are many blocklist providers the main ones being Spamhaus, Barracuda, Spamcop, Spamrats, SenderScore.
When an email server recieves an email it will check with the blocklist if the sender is listed. If it is, it may block the email, mark it as spam or put it in the junk mail folder.
The different blocklist providers have different methods to be delisted, most have a form your can fill out. But if your sender reputation is low.
If your email sender reputation is too low and you send email to addresses that dont exist you can become listed. To stay off the list you need to make sure the recipients you are sending to really exist. You can use Real Email to check if email addresses are correct before sending.
If you are continuing to have trouble you should only send to recipients that are active within the last 6 months. For example if they have opened or clicked a link in an email you have sent within the last 6 months.