All RDS Users being disconnected with reason code 3489660929

Question

Hi,

I am experiencing an issue beginning about 2 weeks ago in an RDS environment running Server 2019. The environment consists of 1 connections broker server and 3 terminal servers. Intermittently all users on a server will be disconnected with Event ID 40 and the message with say "Session x has been disconnect, reason code 3489660929" This will happen for all sessions on the terminal server.

I haven't been able to find much about this reason code, so far I have tried disabling client UDP in registry but this hasn't resolved the issue.

Has anyone encountered this before?

Answer 1

This was resolved by uninstalling kb5041578

Answer 2

Hello,

Besides disabling the registry on the client side with >fclientdisableudp, we may also try modifying this setting via group policy on both client and server side.

Using GPO can ensure uniform settings across all clients. Here is the GPO to modify:

Administrative Templates> Windows Components> Remote Desktop Services> Remote Desktop Connection Client> Turn off UDP On Client (Enabled)

Additionally, a similar action must be taken on the server. If UDP is not disabled on the hosts, it can lead to misconfiguration and issues such as disconnected sessions, since it might attempt to establish a connection via UDP when requested by the client. To change this, modify the following group policy:

Administrative Templates> Windows Components> Remote Desktop Session Host> Select RDP Transport protocols (Set this to Use only TCP)

I hope this information helps.

Best regards,

Karlie

Answer 3

Hi Karlie,

Thanks for the steps but unfortunately the issue persists after taking these steps.

Answer 4

Hi there,

I came across a thread online suggesting that this error might be related to the WLAN driver. It would be wise to check for any network adapter error messages in the event log. Additionally, using Wireshark to determine if the issue is caused by the network could be necessary.

Answer 5

I believe I have found the cause. https://support.microsoft.com/en-us/topic/august-13-2024-kb5041578-os-build-17763-6189-522a6305-63d2-40e3-8084-2ab8f9589bc6I'll report back with the outcome