Just yesterday, following the installation of some windows updates, I found myself in a situation where the flow of emails from an exchange 2016 no longer worked. All services were online but both incoming and outgoing emails did not work.
Specifically, all the emails that I tried to send remained in the drafts and from there they did not unpick. Doing a bit’ troubleshooting I noticed a couple of errors that led me to the solution (thanks above all to Google).
In the SMTPReceive logs every incoming connection was blocked with this error:
Rejecting the non-probe message and disconnecting as transport service is Inactive.
While if I tried to send an email to the exchange via telnet, the error I received was this:
421 4.3.2 Service not active
This sent me a little’ in confusion since the transport service was active and even restarting it the situation did not change.
After a while’ by searching the internet I found someone with the same errors. First he advised to see the status of the exchange components with this command:
Get-ServerComponentState -Identity ServerName
And actually all the components were in the Inactive state so the problem was definitely that:
To put them back on I had to give this command:
Set-ServerComponentState -State Active -Requester Functional -Identity -Component ServerWideOffline
Instantly all the components went into the Active state and exchange resumed managing emails by creating queues for delivery and receiving all messages queued on the antispam.