I'm currently working with Exchange Online and we use Outlook Classic for our email communication. We have several devices on our network that need to send reports via email to our clients. I've set up an SMTP service on one of our Windows Server 2022 machines, using IIS 6. However, when I try to send a test email to myself through that SMTP server, the email shows up in the Queue folder. Interestingly, when I direct the network device to send an email to a Gmail account through that SMTP setup, it goes out (even if it lands in the junk folder), but I can't seem to get it to send to our Exchange Online service. Any ideas on what I'm missing?
5 Answers
Make sure to check your outbound connectors configuration in Exchange Online. If they're not set up correctly, that could be why your emails aren't going through.
You might want to consider using a service like SMTP2GO, especially since you're sending emails to clients. Microsoft has a policy against relaying external emails through their service, and SMTP2GO allows for better reliability and features like DKIM signing.
We use IIS as an SMTP relay, and while it’s mostly functional, it does have its quirks, especially with TLS certs. I'm actually testing a migration to Postfix, and it's working really well so far. I could share my current configuration if you're interested.
Why not just direct your SMTP traffic straight to Exchange Online using direct send? It could simplify your setup.
We have a local Exchange set up in a Hybrid configuration for this type of thing, but with the upcoming changes from Microsoft, we're considering alternatives.
Related Questions
Can't Load PhpMyadmin On After Server Update
Redirect www to non-www in Apache Conf
How To Check If Your SSL Cert Is SHA 1
Windows TrackPad Gestures