There are invalid mail header fields.

This type of error appears in the Additional headers field within the Mail tab when you input a line of strings in an incorrect format in a mail header field.

A correct mail header field is composed of a field name, followed by a colon (“:”), and then a field body. A field name must be made up of the printable ASCII characters (except for the colon and space).

These are valid mail header fields:


These are invalid mail header fields:

Cc // Missing colon
Reply To: // Space in the field name

Just another contact form plugin for WordPress. Simple but flexible.