When the MassMailer Email Verifier returns the status 'Invalid' we flag the Contact or Lead as Invalid meaning we turn the 'Invalid Contact', 'Invalid Lead' custom field to TRUE.
Please note that the Invalid Leads or Invalid Contacts are automatically suppressed from emailing from MassMailer.
EMAIL ADDRESS INVALID
The email address format is incorrect. For example, james0uwerwe#com is not in the correct email format of firstname.lastname@example.org. Many of these can be prevented by applying simple regular expression to data prior to verification.
EMAIL DOMAIN INVALID
The email address is associated with a domain that doesn't exist. For example, massssmailer.com is not a real domain capable of sending and receiving email. So email@example.com is an invalid email since it pertains to a domain that does not exists.
EMAIL ACCOUNT INVALID
The email account (the inbox) does not exist at the given domain. For example, firstname.lastname@example.org results in a secondary status of email_account_invalid.