Using a mask on a cfinput field causes the email to not go through. I remove the mask and the email is sent fine.
<HTML>
<HEAD>
</HEAD>
<BODY>
<cfform method="post" action="submit2.cfm" name="theform">
<cfinput type="text" name="SSN" size="30" mask="999-99-9999">
<input type="submit" name="submit" value="Submit">
</cfform>
</BODY>
</HTML>
and
<CFMAIL
TO="[email protected]"
FROM="[email protected]"
SUBJECT="?">
<cfoutput>
#Form.SSN#
</cfoutput>
</CFMAIL>
it works for me as is(CF9), but since your are on CF8 try adding the cfmail type.