Not receiving email of new order and customer also never receive email suddenly

[meimeisi]

hi! i am using prestashop 1.5.4.1 for almost a year and suddenly i started to encounter issue below and i actually never change any settings or update any new modules etc before the issue. 

 

1. i only receive email of paypal notification of new order but i never receive email sent from my PS to my yahoo mail (I am using yahoo.com email all the while)

2. my customers also feedback they never receive email of order confirmation too.

 

When i tried to send a test email from my back office to my yahoo mail, it didn't go through. I submitted message through CONTACT US from front office, i still never receive email.

 

So, i went to research and i started to use SMTP setting. Initially, i could still receive email as usual.

 

However, the issue has started again now. I couldn't even send test email at all..

 

Attached the printscreen for the latest updates.

Could anyone help on this? I am really upset that PS seems to keep giving me new problem/glitch.

[meimeisi]

I have message from my web hoster,

 

[email protected] R=lookuphost T=remote_smtp: SMTP error from remote mail server after end of data: host mta7.am0.yahoodns.net [98.138.112.32]: 554 5.7.9 Message not accepted for policy reasons. See http://postmaster.yahoo.com/errors/postmaster-28.html

 

It's due to yahoo policy issue?