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Outbound ,ail flow issue in exchange server 2016.
Certain emails emails with size of 100 kb or large and with attachments get queued in exchange due to this notorious error [{LED=450 4.4.318 Connection was closed abruptly (SuspiciousRemoteServerError)}
My send connector is health and can send emails to certain domain without issues.
The default send connector inactiveconnectiontimeout and messagesize settings is fine.
My firewall does not show messages being dropped or denied.
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The temporary solution that have used to get rid of this is:
Create a separate connector**(only set require TLS)** for that specific domain whose recipient mails is being queued, then restart transport service. But is not the right way to handle it because its unhealth to keep on restarting the transport service since it impacts the entire exchange organization.
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Hi @Benard Mwanza ,
As far as I know, there are various factors that may lead to the error "{LED=450 4.4.318 Connection was closed abruptly (SuspiciousRemoteServerError)}" so it might be hard to find out the root cause.
For your situation, could you run the get-messagetrackinglog for one of the problematic messages and share the output after removing all personal information involved?
Get-TransportService | Get-MessageTrackingLog -MessageSubject <subject> -Sender <mailbox address> -Recipients <mailbox address> -Start <start time> -End <end time> | select timestamp,EventID, Source, ConnectorID |sort-object Timestamp
Besides, it's suggested to enable the protocol logging for the connectors involved and see if more clues can be found from the logs.
Hi @Benard Mwanza ,
Just checking in to follow up with this thread. Should there's any update or additional information, you can feel free to post back.