E-Mail Stuck as Failed in MailSpool

Hi CreateShare,

Thanks for reaching out, and welcome to the Sophos Community! 

Please check out the MTA configuration on your firewall as per the following documents: 

• Configure email protection in MTA mode
• Scan inbound and outbound SMTP traffic

In your case, check if there's a default SMTP/SMTP scan rule that is turned on. Also, do you have multiple WAN interfaces or just one? 

Legacy Mode: 

In Legacy Mode, SF acts as a transparent proxy that scans emails for malware and spam, applies SPX Encryption and Data Protection. Refer to the following guides to see how SF can be configured to scan email traffic in Legacy Mode:

MTA Mode:

In MTA Mode, SF acts as a Mail Transfer Agent. A Mail Transfer Agent (MTA) is a service responsible for receiving and routing emails to their specified destinations.
Deploy SF in MTA Mode when you want it to perform actual routing of emails compared to Legacy Mode, where SF only forwards the email traffic as a proxy.
In MTA Mode, SF performs the following functions:

• Performs relaying and routing of emails. You can configure relaying of emails from Email > Relay Settings.
• Protects multiple Email Servers using SMTP Policies. From Email > Policies > SMTP Policies, you define the kind of protection you want to apply on each of your Email Domains.
• Displays email messages that are either waiting or failed to be delivered in the Email > Mail Spool.
• Displays logs for all the emails processed by the Device from Email > Mail Logs.

Reference: Sophos Email Help

Thanks,

Hi CreateShare,

Thanks for reaching out, and welcome to the Sophos Community! 

Please check out the MTA configuration on your firewall as per the following documents: 

• Configure email protection in MTA mode
• Scan inbound and outbound SMTP traffic

In your case, check if there's a default SMTP/SMTP scan rule that is turned on. Also, do you have multiple WAN interfaces or just one? 

Legacy Mode: 

In Legacy Mode, SF acts as a transparent proxy that scans emails for malware and spam, applies SPX Encryption and Data Protection. Refer to the following guides to see how SF can be configured to scan email traffic in Legacy Mode:

MTA Mode:

In MTA Mode, SF acts as a Mail Transfer Agent. A Mail Transfer Agent (MTA) is a service responsible for receiving and routing emails to their specified destinations.
Deploy SF in MTA Mode when you want it to perform actual routing of emails compared to Legacy Mode, where SF only forwards the email traffic as a proxy.
In MTA Mode, SF performs the following functions:

• Performs relaying and routing of emails. You can configure relaying of emails from Email > Relay Settings.
• Protects multiple Email Servers using SMTP Policies. From Email > Policies > SMTP Policies, you define the kind of protection you want to apply on each of your Email Domains.
• Displays email messages that are either waiting or failed to be delivered in the Email > Mail Spool.
• Displays logs for all the emails processed by the Device from Email > Mail Logs.

Reference: Sophos Email Help

Thanks,

Hi CreateShare,

Check out step 9 from the following KBA for more information: 

• Mails are not delivering and getting an error “defer (-53): retry time not reached for any host”

Thanks,

1. No, SMTP Scanning was not enabled in LAN TO WAN SMTP Rule for Exchange. Do we still need to enable SMTP scanning in the rule even in MTA Mode?

2. Yes, I have two Internet Gateways.