No value for sendmail_from, user registration email not sent

[shacker]

WP installed in cPanel add-on domains do not send welcome messages to new WP users.

Watching the exim_reject_log shows:

F=<> rejected after DATA: there is no valid sender in any header line

...

Envelope-from: <>

...

F From:

phpinfo(); confirms that the sendmail_from property has "no value."

Adding this to .htaccess :

php_value sendmail_from user@…

causes phpinfo() to show a valid value, but attempting to register a new user still shows exim refusing to send the message because there is "no valid sender."

A simple PHP mail test script in the same dir works fine.

No traction in almost a year, so closing as wontfix.

Feel free to re-open it if you have additional information/suggestions/patches/...