A complaint occurs when an email recipient marks an email message as spam by clicking “This is spam” or “send to spam folder” in their web email client. The Internet Service Provider (ISP) records this as a complaint. MoonMail is really strict here:
Your complaint rate should be less than 0.085 %
If any of your campaigns gets a higher rate, for instance, 0.1 %, your account will be immediately blocked.
Hard bounce: When the email address is invalid or doesn’t exist. We can help you detect those and remove them from your list before sending a campaign. Contact support for more information.
Soft bounce: When the email is not currently available for a temporary reason that could include the mailbox was full, the server was down, or the message was too large for the recipient's inbox.
If bounces are not addressed, these can have dramatic consequences to your account, sometimes going as far as getting it suspended. MoonMail is still really strict here:
Your bounce rate should be less than 4.50 %
If any of your campaigns gets a higher rate, for instance, 5%, your account will be immediately blocked.