Some order status emails wont send whilst others will?

[weeme]

When users create accounts and place orders they receive the automated emails no problem, however when I manually change a status for example, Pending Payment to Payment accepted, or mark an order as shipped, these status emails fail to deliver and I receive the following email from MAILER-DAEMON 

 

**Message you sent was blocked by our bulk email filter**

Your message to: [email protected]

was blocked by our Email Security Gateway. The email you sent with the following subject has NOT BEEN DELIVERED:

Subject: [SHOPNAME] Payment accepted

 

I'm very confused, I have SMTP emails set up on prestashop, the test emails work no problem, customers receive emails upon account creation, upon placing orders, when using the customer service function, it all works correctly and the emails send as they should which leads me to believe this is not an issue with my email configuration or host? 

 

Any help would be appreciated

Thanks

 

[weeme]

Solved : Was hosting issue, some emails being flagged as spam, hosts resolved and now working