Not receiving emails
Sunshine sends emails when an order is placed: one to the site admin and a receipt email to the customer. If you are not receiving these emails, please follow these steps:
Obligatory: Check your spam folder.
Confirm you have the right email address in the settings. Go to Sunshine > Settings > Email > Notifications
Add an Email Log plugin which will track any time WordPress tries to send an email. This is to confirm they are being sent at all. If sent emails are showing in the log, then check with your web host to determine the underlying issue.
Are you receiving emails from other areas of your site, such as a contact form? If not, this is a global issue and not specific to Sunshine. Disable all other plugins and test again. If it works, then you have identified there is a conflict. Enable plugins one by one and testing after each until it breaks again and you have then identified the conflict.