OFF-TOPIC: Community board using wrong sender address

This is off-topic here, but I could not find any decent contact address for the community board.

Mail notifications from Dell Community are rejected by a lot of ISPs because the sender address is in a non-existent domain

Sep 25 17:13:03 lxmhs89 postfix-postrelay/smtpd[84729]: NOQUEUE: reject: RCPT from smtp.lithium.com[208.74.204.5]: 550 5.1.8 
 
  : Sender address rejected: Domain not found; from=
  
    to=
   
     proto=ESMTP helo=
    
   
  
 

Could someone with contacts to the admins please forward this?