The emails from freshservice were earlier sent through SendGrid, our former email service provider. However now, we have migrated to our own SMTP servers. 

If you would like to use your own mail servers instead of our SMTP servers to send and receive emails, you can use the custom mail server option available.

You could set this up by adding the IMAP and SMTP details of your mail server to your freshservice account under, Admin > Support Channels > Email > Click on the Email > Use your own mail server.

Setting up your support email address