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StefanoC66's avatar
StefanoC66
Iron Contributor
Dec 12, 2024
Solved

SMTP Delivery to Mailbox fails

We have an exchange 2013 server in the Org and we added an exchange 2019 server on windows 2022.

We got an issue where Exchange 2013 cannot forward email to exchange 2019 mailboxes due to SMTP error.

In the log files we found 

 

we checked the TLS configuration on the exchange 2019 and TLS1.1 and 1.2 are enabled

what can be the issue ?

 

  • Solved , apparently, checking the TLS configuration on 2013 and configuring the "client" portion which wasn't configured via registry

6 Replies

  • StefanoC66's avatar
    StefanoC66
    Iron Contributor

    Solved , apparently, checking the TLS configuration on 2013 and configuring the "client" portion which wasn't configured via registry

  • Dan_Snape's avatar
    Dan_Snape
    Bronze Contributor

    Run the Exchange Health Checker script across your 2013 server (and worth running on your 2019 server as well just to make sure). It should advise you what you need to do. Most likely this is a TLS misconfiguration (You should disable TLS 1.1 to increase security)

    • oyimafuEmma's avatar
      oyimafuEmma
      MCT

      we are having issue with our on-prem exchange server 2019.

      if a user whose mailbox is on-prem try to send email to organization exchange online mailbox the mail get delivered for some user and not delivered for others with this error on the queue viewer
      LastError : LED=451 4.4.397 Error communicating with target host.  421 4.2.1 Unable to connect  SocketTimedout: Socket error code 10060};{MSG=};{FQDN=};{IP=192.168.100.4 LRT=12/19/2024
      10:30:44 AM

      i have confirmed the MX record properly configured.

      The send connector was configured to route mail using smart host

      please what should i check.

    • StefanoC66's avatar
      StefanoC66
      Iron Contributor

      Hello Dan_Snape 

      I already ran the healthchecker on both and as per the TLS it was enabled TLS1.0,1.1,1.2 on Exchange 2013 and only TLS1.2 on 2019.
      I enable TLS1.0 and 1.1, just to have a try, on 2019 but didin't solve.

       

    • StefanoC66's avatar
      StefanoC66
      Iron Contributor

      No, as I said in my post it fails TLS authentication