I am migrating our applications from Windows Server 2012 R2 to Windows Server 2022 Standard.

During testing, I found that our app on the 2022 server is unable to send emails to SendGrid over port 587.

I installed telnet and attempted to connect with:

telnet smtp.sendgrid.net 587

After a minute or so, I get “Connecting To smtp.sendgrid.net…Could not open connection to the host, on port 587: Connect failed”

The same command on Windows 2012 R2 works and will open a connection.

I’ve tried setting up an outbound firewall rule for port 587 on TCP and UDP with no success. I’ve also tried disabling the firewall.

What am missing? I don’t think it’s directly related to SMTP or SendGrid. Seems like there is a security policy that is blocking that port.