SMTP test fails due to congestion.

[JohanValstar]

I wanted to test my SMTP server via 'Microsoft Remote Connectivity Analyzer' but it fails often. It uses IP address 52.109.76.22 to connect to my mail server. (Exchange Server 2016 on Windows Server 2016).During these test, I see that the remote end set the Flags (CWR & ECN) for congestion and my server send retry messages.After 2 retries, server reset the connection:And due to this reset, the smtp test fails.How it can be that network becomes congested? II do have a Fiber connection (100Mbps Up/Down = 200Mbps bi-directional).I did a capture trace at the WAN site and also at the LA

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