Hey Rowan,
I am sorry for the delay of this reply,
It seem like these email address is not valid which you set it from backend > Easysocial > settings > general > emails tab > Sender e-mail address - info@spanisharks.com
You can check my first screenshot which I trying to send a test email to this email account (info@spanisharks.com), but it I received back mail server response :
This is an automatically generated Delivery Status Notification.
Delivery to the following recipients failed.
info@spanisharks.com
Then I switch to use website@spanishmarks.com email address instead. It should work perfectly now.
Can you give it a check now?