Im using odoo 11 CE and i have configured the outgoing mail server with my host settings. the connection test passes.

Ive setup users to have notifications be handled by email.

The users are following the chatter threads.

Ive enabled external email server

I can send password resets, I can send emails from the technical settings -> email -> emails.

but i cant get the chatter email notifications to work.

I must be missing something, I dont require the inbound mail so i have set the alias to blank

users have no alias set.

If i set an alias in general settings I get and error when i send and email from technical settings -> email -> emails

bounce+6@mydomain.com  

Any help much appreciated 

Thanks