In order to track email status, make sure you provide the CNAME records under IT Administration > Email Configuration, otherwise there will be no tracking for "Clicks" and "Opens".
Mail systems typically use a hidden image embedded in the message and track when that image is loaded. That's said, "Opens" tracking will not work if the recipient does not "allow images" from the sender.
Freshdesk Customer Success collects statistics on the campaign for 30 days. After 30 days, the campaign results won't be updated. Responses from the campaign recipients won't be received after 30 days since the campaign was run.
The campaign statistics are not real-time, they will be updated on an hourly basis.
Failure typically means it was rejected by the mail server or the mail bounced.
There are a few reasons why an email fails to be delivered to a recipient:
Recipient emails are not valid
Mail-from address does not match your domain
Some organizations have policies to reject emails coming from bulk email (for security reasons)
It is important that you:
Use the mail-from domain associated with your domain
Have MX records for the domain you associate with the mail-from address
Make certain the domains listed in the From, Sender, and Mail-From headers match each other with your domain configured.