Hi Guys,

I am sending emails from my domain(A) to another domain(B) and (C).Domain C users are getting emails without any problem.Now the users from domain B are getting the following error

Your message wasn't delivered due to a permission or security issue. It may have been rejected by a moderator, the address may only accept e-mail from certain senders, or another restriction may be preventing delivery.

Diagnostic information for administrators:

Generating server: s16062114.onlinehome-server.info

5.7.1 smtp; 554 5.7.1 Error: need authentication from 87.106.250.xxx> #SMTP#

I am using phpmailer class to send the emails.The host is 1&1.

Can you please let me know if

1.The mail sever from domain B is under a firewall and I have to use smtp for authentication?

2.If yes then is there any example how to use smtp with phpmailer class.

Thanks in advance.