Mail bounces back as "relaying not allowed" or sim

[rancher]

So - I am not whiz at this stuff, but have valid press releases that need to be sent for my clients. Not spam. However, an inordinate number come back as "relaying not allowed". Could use a little help - are there settings I have missed?
Thanks for any sugggestions
rancher

 

[stanbusk]

Could you copy the full bounce content? (replace sensitive info with * if necessary).

 

[rancher]

Will do - probably will have to make up a dummy listt

as the list I am sending to is 700 some long and don't want to send it out yet. Will try to get this done. thank you for your help
rancher