SMTP username

Isn't it easier to change the username?

If you're using PunBB 1.1 or later it should only be a matter of changing maxlength="25" to a higher value in admin_options.php. If you're using an older version, it's a bit harder. The line to edit is line 395.

Hmm, you say it didn't help. What happens then?

Aha. If you read the page it links to, there appears to be a problem with linebreaks in the mails sent out by PunBB. I'll have a look at it later tonight.

Try this. Open up include/email.php and locate the row:

$headers = 'From: '.$from."\n".'Date: '.date('r')."\n".'MIME-Version: 1.0'."\n".'Content-transfer-encoding: 8bit'."\n".'Content-type: text/plain; charset='.$lang_common['lang_encoding']."\n".'X-Mailer: PunBB Mailer';

Replace it with

$headers = 'From: '.$from."\r\n".'Date: '.date('r')."\r\n".'MIME-Version: 1.0'."\r\n".'Content-transfer-encoding: 8bit'."\r\n".'Content-type: text/plain; charset='.$lang_common['lang_encoding']."\r\n".'X-Mailer: PunBB Mailer';

And see if that helps, if it doesn't just say so and we will try something different.

Yes, I believe it is. On top of what you edited above, try adding the following directly after that row:

$message = str_replace("\n", "\r\n", $message);