Replacing Send Connector Certificate

I ran into this problem today, and unfortunately this did not fix the issue. Here is how i fixed it.

First (fail) I re-ran the HCW and linked the send connector to the new certificate and tried to remove the old one. Still failed with the same message.

Luckily, we are still in the testing phase of O365 mail, so I just deleted the ‘Outbound to Office 365’ send connector, deleted the old certificate and re-ran the HCW.

In a full production environment, this will break mail flow, so use wisely! Hope this helps someone else out.

I tried this method and Set-SendConnector returned a message that it had completed successfully but not made any changes. Unfortunately the issuer and subject of my old and new certificates are exactly the same, so I assume Set-SendConnector isn’t able to tell the difference. What I ended up doing was temporarily setting the connector to use one of the other Exchange certificates so that the identifiers WERE different, long enough to delete the expired certificate and then set the connector back to the correct and non-expired certificate. As warned above, this will probably stop mail flow but should take only a minute or two to accomplish.

Satheshwaran – thanks a lot.. this worked for us.. after a few hours of troubleshooting much appreciated! great work. cheers!

Cheers thank you for the post – worked like a charm! 🙂

I am getting an error

WARNING: The source Transport servers specified for the connector aren’t in the same Active Directory site.

we have 4 servers split across two AD sites. how do I go around this error?

Thank you

Michael

You saved my ass today 🙂 our sysadmin left, and I got put in charge of mail servers. Our hybridext cert expired yesterday and even though I had renewed it, I didn’t realize the send connector would need updated (since we didn’t request an identical replacement with the same thumbprint). MS documentation was way too involved for me to find this little tidbit that I needed. Thanks a million.

Thank you, thank you, thank you. 2 Hours on the phone with M365 support getting nowhere when I finally came across this post and it worked like a charm!

Worked perfectly thanks.

Its worked me perfectly. Thanks for the Article.

Man, thanks so much for saving my face!

Its worked me perfectly. Thanks for the Article.

This will update all send and receive connectors to the same certificate:
$cert = Get-ExchangeCertificate -Thumbprint XXXXXX
$tlscertificatename = “$($cert.Issuer)$($cert.Subject)”
$connectors = Get-SendConnector | Where-Object {$_.TlsCertificateName -ne $Null}
foreach ($connector in $connectors){Set-SendConnector -Identity $connector -TlsCertificateName $tlscertificatename}
$connectors = Get-ReceiveConnector | Where-Object {$_.TlsCertificateName -ne $Null}
foreach ($connector in $connectors){Set-ReceiveConnector -Identity $connector -TlsCertificateName $tlscertificatename}

You just saved my butt today. I had two Receive Connectors that wouldn’t enable STARTTLS because they could find the old expired certificate. Used your instructions to update the TlsCertificateName and they’re now online and happy. Thanks!

Thanks you, this worked like a charm. however the old certificate is still showing that it is in use by the SMTP service, how would we find out what is using it

I’m so glad I looked into this before trying to wing it! We indeed have the same issuer/subject as the old certificate, so it was good to have a plan going in. I appreciated the pointers on that piece, and the idea to assign a random certificate, so you can delete the old one, then set the new one.
On a different post I saw someone suggest setting it to null, and I did do that and I can confirm that it did work. Not a ton easier, but a little easier than assigning a different cert so I figured I’d mention it.

Set-SendConnector “Outbound to Office 365” -TlsCertificateName $NULL

Thanks again this was a life saver!

Items that I used to expand:
#Get the thumbprint for the new certificate:
Get-ExchangeCertificate
# This listed quite a few certificates, I didn’t know which certificate was the correct one
Get-ExchangeCertificate -Thumbprint | Format-List *
#gives more details on the certificate to validate the correct one and correct dates. before proceeding

#Send Connector – to find out for sure what you need next for the O365 connector. Used this to validate that I was using the correct send connector
get-sendconnector

#Receive Connector – to list out all the connectors and find out what exactly is needed for the “MY-EXCH01\Default Frontend MY-EXCH01”
Get-Receiveconnector

Hello, We have Hybrid wizard completed, but we are not using Office 365 to mailflow emails still going from onsite exchange, but we need send between Exchange and office 365 emails. I know our certificate expired, can I just rerun Hybrid wizard and it will replace certificate?