[Desperate] PHP sendmail with mynbb

[jpenguin]

Ubuntu 12.04 VPS

The people at the MyBB forum have not responded. I need to set up email for my MyBB dforum; but when I try to send an email from the forum, I get

The mail server does not understand the MAIL FROM command. Reason: 550 5.7.0 Sender address does not belong to logged in user {mp-us008}

I tested http://docs.mybb.com/Help-Mail.html on my server and it worked. Any ideas to send mail through my forum?

The pertinent lines in php.ini are

; For Unix only.  You may supply arguments as well (default: "sendmail -t -i").
; http://php.net/sendmail-path
sendmail_path =  /usr/sbin/sendmail -t -i -f webmaster@thelurnarrepublic.cu.cc

[sixonetonoffun]

Did you read this thread from there?
http://community.mybb.com/thread-38084.html

[jpenguin]

OK, now I have something that works. I set the board up to use GMAIL's SMTP server. I was trying to get PHP mail() to work, but I guess SMTP will work