Do you get the 'Your message has been sent as email to the user.' success message after sending?

yes, and when I set the debug mode to "2" in _advanced.php I get the following error report when using the email message form:

(note: substitutions for email addresses were made below)

Backtrace:
debug_die( "Sending mail from «admin <clicks@mymail.net>&raq..." )
File: C:\Inetpub\wwwroot\mysite\inc\_misc\_misc.funcs.php:2067
send_mail( "admin <myAdmin@mymail.net>", "Re: Second post", "sdfgsdgdfgdsg-- This message was sent via the messaging syste...", "admin <myAdminAcct@mymail.net>" )
File: C:\Inetpub\wwwroot\mysite\htsrv\message_send.php:234
Ignored last: 1

Again, the send comment function is sending comment related info via email without issue.

Clicks

"send comment" uses the same function (send_mail()).

It would be more instering what's above the "Backtrace". But I think it says "FAILED"?!

I think you have to digg into _misc.funcs.php's send_mail() method and experiment, what's the part which causes it to fail.

I'll correct the places, where the return code of send_mail() does not get used.. (it should not say that the message had been sent) :/

Sorry, yes, this is the: Additional information about this error:

Sending mail from «admin <me@mymail.net>» to «admin <me@mymail.net>», Subject «Re: Important information» FAILED

Clicks

Maybe it may help already to set error_reporting to E_ALL and display_errors to "on". For $debug > 1 you should see any notices or warnings with the call to mail().

I think you just lost me.

set error_reporting to E_ALL and display_errors to "on". For $debug > 1 you should see any notices or warnings with the call to mail().

Where and how do I do this?

Clicks

php.ini or with ini_set().

See http://manual.b2evolution.net/Debugging#Blank_pages

I used ini_set in /conf/_basic_config.php - no change.

Here's the warning messge that appears at the very top of the display errors page:

Warning: mail() [function.mail]: SMTP server response: 501 5.5.4 Invalid Address in C:\Inetpub\wwwroot\mysite\inc\_misc\_misc.funcs.php on line 2067

Thanks for your help.

Clicks.

What "no change"? There is actually the Warning..!?!

Or has it been there before? If so, you should have told us, of course..

Can you please try the following code:

<?php
error_reporting(E_ALL);
ini_set('display_errors', 'on');
$email = 'foo@example.com';

$i = 0;
foreach( array( $email, "test <$email>", "\"test\" <$email>" ) as $e )
{
  $i++;
  if( ! mail( $e, "Test $i", 'Test' ) )
  {
     echo "Number #$i ($e) failed.\n<br />";
  }
}
echo "end.\n";
?>

(put that into a single file, change the $email to yours and call it through the browser).

Which ones fail?

There is actually the Warning..!?!

Yes, but the warning only appeared after ini_set

I will try the code.

Thank you.

Clicks

It renders a blank screen

You've said "no change", but the Warning (as expected/hoped appeared). That confused me, because there _was_ a change.

Anyway, there should be not problem with the other email address/format then, if you've not obfuscated it too much, because

Sending mail from «admin <me@mymail.net>» to «admin <me@mymail.net>», Subject «Re: Important information» FAILED

"admin <me@mymail.net>" is like the second example in the test you've just tried..

Can you send a mail to the address that fails, as stated in the error/failed-message, through an email client?

Can you send a mail to the address that fails, as stated in the error/failed-message, through an email client?

Yes.

Sorry if I confused you. I will try to work with this a bit more to see what I can find out.

Thanks.

Clicks.

Just to be sure, add

error_reporting(E_ALL);
ini_set('display_errors', 'on');

at the top of the test script.. there may be a fatal error and therefor the blank page. I'll update the script above, also putting an "ok." at the end.