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I have a domain joined Windows Server 2019 OS with Exchange Server 2019 installed. This is a new setup. I am currently trying to add a receive connector which you can see below but I am receiving a error. It seems like Exchange Server 2019 CU11 has a bug in it.
What happens if you enter the specific NIC IP Address under bindings instead of all?
Looks like it saved this time around and it is listening on the port. Weird that the "any" address label is causing the web ui to break.
I have a device that is attempting to send anonymous mail to that receive connector. I have the below error even though I have anonymous authentication option selected. Any ideas on why that may be?
Sender rejected. [xxx@Stuff .com]530 5.7.57 SMTP; Client was not authenticated to send anonymous mail during MAIL FROM . Typically, SMTP server's do not reject emails based on the sender's email. If the receiving end is under your control, check its logs to see why is it rejecting the sender.
Your connector is listening on port 2626. Did you send that message to that port?
What is the goal of this custom receive connector?
Why not just send the emails using the standard port 25?
@Andy David - MVP
Port 25 is blocked so a proxy is used which forwards mail on port 2626.
I can see in the proxy application that mail is trying to send to Exchange Server on port 2626 but is having issues hence the error message I posted above.
Enable Protocol logging and then send some test messages. Check the logs, it should show which receive connector is being used:
https://learn.microsoft.com/en-us/exchange/mail-flow/connectors/configure-protocol-logging?view=exchserver-2019#use-the-eac-to-enable-or-disable-protocol-logging-on-a-connector
Rebooted the server and seeing the below error now.
Receiving server has rejected your message temporarily. 451 4.7.0 Temporary server error. Please try again later. PRX2
Tried the solution here also.
https://www.sonicwall.com/support/knowledge-base/email-flow-issue-with-following-error-in-smtp-mta-log-451-4-7-0-temporary-server-error/170504832918369/
Still looking for solutions...
Sure what you are doing is allowed by your ISP? that error could also be anti-spam greylisting.
I would still enable protocol logging as I mentioned above and see what shows,
Sure what you are doing is allowed by your ISP? that error could also be anti-spam greylisting.
Yes. Port 25 is blocked by all providers (VPS, Cloud, etc.) not just ISPs, unless you file a exception request. However, in my case, I would still be fighting the same issue with Exchange Server so what port I use doesn't matter in the end.
I would still enable protocol logging as I mentioned above and see what shows,
Enabled on my custom receiver.
I guess rebooting must have restarted some service that didn't apply a change I made. I can receive mail now on my custom port. Yay!
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Hi @Pie ,
Glad hear that your issue has been solved and thanks for you sharing. :)
Please mark the helpful replies as answers, this will make answer searching in the forum easier and be beneficial to other community members as well.
Thanks for you understanding.
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It's not about whether the connector is working or not, it's just about modifying binding on receive connector despite the IP/port combination is not in conflict with those of other connectors.
I think this is a bug on Exchange 2019, even on the latest CU12. If you don't get it right in the first place when setting the connector and you come back to modify the binding, either the IP address or port number, then you will get this error. In my case, restarting the server right after the the connector is created/setup (with binding details that we want to further modify) doesn't work. Not sure how long to wait, I just leaved it to the next day and the binding can be modified without problems.