Problem with mail delivering via SSL error 454 4.7.4

Copper Contributor

Hi we have problem with delivering mail from fortimail appliance to exchange 2016 infrastructure, sometimes emails stuck at fortimail and not delivered to exchange with this message: 

 

dsn=4.0.0, stat=Deferred: 454 4.7.4 temporarily failed to deliver message via SSL/TLS.(Reason:454 4.7.4 temporarily failed to deliver message via SSL/TLS.)

this errors ocasionally occurs and emails are going to timeout and not delivered after few days,

I cannot find nothing about this error code, and to troubleshoot.

 

Thank you

1 Reply

@Jozi Zurbej 

 

Hi,

 

The issue can be caused by one of the following reasons:

  • The Exchange server is experiencing Time synchronization issues.
  • There is a replication issue between the domain controllers.
  • The Exchange server is experiencing Service Principal Name (SPN) issues.
  • The required TCP/UDP ports for the Kerberos protocol are blocked by the firewall.

https://docs.microsoft.com/en-us/exchange/troubleshoot/client-connectivity/454-4-7-0-temporary-authe... 

https://www.thecloudtechnologist.com/how-to-fix-exchange-online-hybrid-outbound-connector-454-4-7-5-... 

Regards,

MD