Order and payment confirmation emails

Processing payments through paypal (still in sandbox), the seller does not receive any confirmation emails... Everything else worked properly except for this small issue!!! All the email defined in both Joomla parameters and Hikashop are ok. What could be the potential root cause for this? Could it be the SMTP host? I'm able to receive other emails from joomla such as private messages notifications.

Nothing happens on the vendor side when creating an order and the problem is that i'm not sure how I can kinda route the email to see where it's getting blocked ....

Please help