Some SMTP Servers are persnickety about the from field when the email is sent from a php script. some servers may not recognize the from name setting, this should sometimes be left off.
In some cases, it may be best to use a hard codded form email address and from name, and use the dynamic values for the Reply to address and return path settings.
Though the organization and x-mailer settings are technically optional, some SMTP server may not like if they are left blank.