The “Corrected_Do_Not_Mail” column within the insert file can be switched on or off at an account level.
This column allows emailHygiene to automatically make corrections to email domains that may not appear to be valid initially. When we make a correction, the original incorrect email address is moved into this column.
The corrected email is placed in the email address column. An email flag is given to the corrected email address, since the incorrect email address would typically be given a “D” for a deliverability issue.