Error on clean install for Microsoft Entra Connect Sync v2.4.18.0 HTTPRequestException

Question

After clean install of Entra Connect Sync v2.4.18.0 using TLS v1.2, after global administrator authentication and MFA prompt, I receive HttpReqeustException An error occurred while sending the request. Has anyone seen this and know how to bypass?

I've tried reboot, TLS 1.2 verification, /InteractiveAuth.

Tracelog shows ---> (Inner Exception #0) System.Net.Http.HttpRequestException: An error occurred while sending the request. ---> System.Net.WebException: The underlying connection was closed: An unexpected error occurred on a send. ---> System.IO.IOException: Unable to read data from the transport connection: An existing connection was forcibly closed by the remote host. ---> System.Net.Sockets.SocketException: An existing connection was forcibly closed by the remote host

Answer 1

@Richard Cook

Thank you for posting this in Microsoft Q&A.

As I understand you are getting an error while installing latest version on AD connect in your environment.

As per the error the communication is not happening between your AD connect server and Entra ID. This communication happens over TLS 1.2. And you have already mentioned in your query that TLS 1.2 is enabled, and also you have rebooted the device and checked.

Microsoft Entra Connect (version 1.1.614.0 and after) by default uses TLS 1.2 for encrypting communication between the sync engine and Microsoft Entra ID. If TLS 1.2 isn't available on the underlying operating system, Microsoft Entra Connect incrementally falls back to older protocols (TLS 1.1 and TLS 1.0). From Microsoft Entra Connect version 2.0 onwards. TLS 1.0 and 1.1 are no longer supported and installation will fail if TLS 1.2 isn't enabled.

You can try to enable TLS1.2 again and reboot the device.

You can run PowerShell script mentioned below article to enable TLS 1.2.

https://learn.microsoft.com/en-us/entra/identity/hybrid/connect/reference-connect-tls-enforcement#powershell-script-to-check-tls-12

Reboot the device once again one TLS 1.2 is enabled and then you can try to install AD connect

This communication issue might also occur if you have proxy set up in your environment.

You can perform steps mentioned in below article to take care of the proxy issues,

https://learn.microsoft.com/en-us/entra/identity/hybrid/connect/tshoot-connect-connectivity#connectivity-issues-in-the-installation-wizard

Let me know if you have any further questions.

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