This is because Perform Zone filters out emails that are not in the correct syntax before sending. As a general rule, illegitimate addresses are those that you do not think are real or do not recognize.
Invalid email addresses:
- example.com (character @ is missing)
- A@b@firstname.lastname@example.org (only one @ is allowed outside quotation marks)
- “0;;<>[\]@example.com (none of the characters before the @ in this example is allowed outside quotation marks)
- this\is\”really\”not\\email@example.com (spaces, quotes and slashes may only exist when within quoted strings and preceded by a slash)