All of a sudden Magento (188.8.131.52) stopped sending new order emails automatically. From backend if I click on Send Email in Sales > Orders > Random Order then the user receive the email, but I have to do it manually.
I checked all the options in Configuration > Sales > Sales emails > Order and Enabled is set to Yes and sender email domain is the same domain of the site.
I have enabled logging in System > Configuration > Developer > Log Settings and checked logs files in magento var/log but there's nothing strange.
I also checked mail server logs, there's no trace of automatically sent emails, i only see entries of manually sent emails