Recently having this issue where reply emails are not sending. Everything was working fine prior.
We confirmed this by creating new emails to addresses ending with Gmail.com and Outlook.com, nothing is received while Freshdesk confirm it's sent.
Double checked Admin > Mailboxes (Email) and Global Support Mail is verified. Double checked Admin > Email Settings > Dkim and domain DNS settings are verified as well. Double checked email host (zohomail) email forwarding is working also.