Luigi's questions

These are the versions of the exchange servers:

Exchange 2016 CU23 - 15.1 Build (2507.6)

Exchange 2010 SP3 - 14.3.0513 Build(123.4)

The problem is sending and receiving emails in Exchange 2016. Creating the send and receive connector in Ex2016:

Without connector to send and by default receive in Ex2016:

Perform tests with Microsoft Remote Connectivity Analyzer. The test mail arrives and passes the tests.Also with Chektls and without problems

Reading on the internet, there are more problems in Ex2010, I was thinking if this problem is corrected by recreating the connectors as done in Exchange 2003 - 2010

Reviewing the RDN message in a little detail, I realize that it only checks the message in Ex2010 and does not ask in Ex2016 if the mailbox exists. I have created test mailboxes on both servers and I can access them in OWA, that is where I have these problems sending and receiving emails

Ex2010 in 10 MX Ex2010.contoso.com

Ex2016 in 20 MX Ex2016.contoso.com

I have an error when sending mail from 2010 to 2003 coexistence:

error 550 4.4.7 queue expired; message expired

This is the version I use to test

Ex2003 |  v6.5 Build 7638.2 SP2    |       6.5.6500.0

Ex2010 |  v14.3 Build 123.4 SP3    |       8.0.535.0

Testing to upgrade Exchange 2003 to 2010. Reference Exchange upgrade guide

There are problems with one of the RGC (Routing Group Manager) connectors, the connector was created again but the same problem continues.

These are the tests that were carried out to send mail:

Reviewing the logs and trying to find any error messages

1. Event Viewer no error.
2. Send queue, there is no error (it is pending).
3. Exchange log, shows error that it did not send 4.4.7 relay.

Checking the possible errors caused by NDR 4.4.7 (MX, DNS, AD, NSLookup) is fine.

1. How can I test the connection between the Exchange Servers?.
2. What logs in ASDEdit should I check if the logs are okay?.
3. What other reason can cause error 550 4.4.7 queue expired message expired?

Practicing with the certificates, in let's encrypt win-acme normal is created, I send and receive normal mail, https in owa and the other services

Testing with checktls, it gives me an alert message :

Cert Hostname DOES NOT VERIFY:

(mail.contoso.com != mail | DNS:mail | DNS:mail.lan.contoso.com)

I don't understand the mail.lan.contoso.com DNS error. I thought the error was the DNS SPLIT, but reading in the forum they comment on something about the error.

I understand that the other connectors should not be changed in forums, books and tutorials, nobody changes them. That is why a new connector is created to receive from the internet, to which the FQDN can be changed.

Recommendations of this forum, my dns settings :

Private AD DNS (lan.contoso.com)

Private DNS (contoso.com) SPLIT

Public DNS (contoso.com)