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Master Invalid List

Contact Lists Updated on December 3, 2021

The Master Invalid List has been added to prevent bounces and help your reputation as a sender. Sending emails to invalid email addresses or sending continuously to the same invalid email address might cause damage to your reputation as a sender. Benchmark Email understands the importance of maintaining our client’s sending reputation. Therefore we introduced features like Reputation Health Score to monitor the health of your database and now the Master Invalid List.


How Does it Work?


After you’ve sent an email campaign, an Invalid Email List is created by our system and added to your account. The list is compiled with the recipient’s email addresses that were marked by an ISP as invalid emails.  The Master Invalid List will only show up in the Contact List Dashboard if and when you send a campaign that contains invalid emails.

The contacts added to the Invalid List are filtered from all future mailings and list uploads. This provides you better options to manage the Invalid Email addresses and also ensures that they are not added back to a List in the future.

Email addresses in the Master Invalid List are considered inactive contacts; therefore, invalid emails are not included in your Total Unique Active Contacts.


How to remove a contact from the Master Invalid List

If you think that an email address was wrongly added as Invalid or the issue due to which it was marked as an Invalid email address (like issues with the Domains DNS settings) has been fixed. You may remove the individual email address from the list and add it back to your regular lists.

Once an email address has been removed from the Master Invalid List and added back to an active contact list, the system will send them emails again.


The following are some code examples given by the ISP’s when a recipient is marked as an Invalid Email.


  • 550 Mailbox not found
  • 550 5.5.0 Requested action not taken: mailbox unavailable
  • 554 5.7.1: Recipient address rejected: Not found recipient account!
  • 550 5.1.1
  • 550 5.1.1 User unknown
  • 550_Invalid_recipient
  • 554 delivery error: This user doesn’t have an inbox (Yahoo, Ymail, AOL, etc.) account.
  • 5.7.1 Unable to deliver to


  • The Master Invalid List cannot be deleted. You can only remove individual contacts from the Invalid list.
  • If you wish to remove a contact from the Invalid list but don’t want to email them again, we recommend adding them to the Master Unsubscribe List.

If you have additional questions, please feel free to contact our support team via Email, LiveChat or Phone.

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