If email replies to Amazon customers are composed in the PlentyONE system but do not arrive in the Amazon seller account, this is usually due to an issue with the provider's SMTP server or missing IP whitelisting. Amazon only forwards messages if the mail server is reachable and emails are not intercepted by server timeouts or whitelist blocks.CauseWhen sending emails, PlentyONE establishes a connection to your external SMTP server. If your firewall or mail server does not allow the IP addresses of PlentyONE or blocks ports, connection timeouts occur (e.g. i/o timeout or dial tcp errors). The messages then remain in the system or are mistakenly archived without being transmitted to Amazon.Step-by-step guide to resolutionTo ensure smooth email delivery to Amazon, proceed as follows:Navigate to the whitelist settings in your local email server or firewall settings.Add all relevant IP addresses of PlentyONE to the whitelist (especially for CloudId: 92 Frankfurt or CloudId: 94 Dublin).Check that the SMTP ports used (e.g. port 587 or po...