P2S connection frequently disconnecting with error "[CMMON32] 15:24:00 26 External disconnect due to lost connection"

Abhijit Jadhav 5

[cmdial32] 11:35:20 03 Event before initialization call process = C:\Windows\system32\rasautou.exe [cmdial32] 11:35:23 04 Event before connection connection type = 1 [cmdial32] 11:35:23 06 Event before tunneling Username = ########-####_MigrationNonProd Domain = DUN setting = ########-dea8-######-8228-###### Tunnel Device name = Tunnel address = azuregateway-#######-dea8-#####-8228- aa9c3####-######.vpn.azure.com [cmdial32] 11:35:24 07 Connection event [cmdial32] 11:35:24 08 Custom Action DLL Action Type = Connect Actions Description = to update your routing table Action Path = C:\Users\x2\AppData\Roaming\Microsoft\Network\Connections\Cm######-DEA8-##### -8228-########1558\CMROUTE.DLL Return value = 0x0 [cmdial32] 15:24:00 13 Disconnect Event Call Process = C:\Windows\system32\CMMON32.EXE [CMMON32] 15:24:00 26 External disconnect due to lost connection [CMMON32] 15:24:00 14 Reconnect Event

Thanks

GitaraniSharma-MSFT 49,401 Reputation points Microsoft Employee

2024-01-23T10:40:44.94+00:00
Hello @Abhijit Jadhav ,

Welcome to Microsoft Q&A Platform. Thank you for reaching out & hope you are doing well.

I understand that your P2S VPN connection is disconnecting frequently with error "[CMMON32] 15:24:00 26 External disconnect due to lost connection".

Could you please share the below details:

What is the tunnel type and authentication type configured for your P2S VPN in the Azure portal?

What is the OS model and version of the client machine on which Azure VPN client is installed?

Is this issue happening on a single client machine or multiple machines?

How is the client machine connected to Internet? Is it wired network or wireless?

Regards,

Gita
GitaraniSharma-MSFT 49,401 Reputation points Microsoft Employee

2024-01-24T14:13:07.5333333+00:00

@Abhijit Jadhav , could you please provide an update on this post?
Abhijit Jadhav 5 Reputation points

2024-01-25T15:40:49.3666667+00:00

Hi @GitaraniSharma-MSFT ,

Below are the details:

Q1. What is the tunnel type and authentication type configured for your P2S VPN in the Azure portal?

Ans: Tunnel type is IKEv2 and Authentication type is Azure certificate.

Q2. What is the OS model and version of the client machine on which Azure VPN client is installed?

Ans: Its 64-bit Windows Server 2019 Datacenter Version: 1809

Q3. Is this issue happening on a single client machine or multiple machines?

Ans: It's happening on multiple machines.

Q4. How is the client machine connected to Internet? Is it wired network or wireless?

Ans: Its standard Azure VM.

Thanks, Abhijit
GitaraniSharma-MSFT 49,401 Reputation points Microsoft Employee

2024-01-30T14:52:14.5233333+00:00

@Abhijit Jadhav , you mentioned that the Azure VPN client is installed on an Azure VM with 64-bit Windows Server 2019 Datacenter OS. Is this correct?

You are not connecting to Azure from a local machine, but you are connecting to Azure VPN on an Azure VM, is that correct?
Abhijit Jadhav 5 Reputation points

2024-01-30T14:58:29.8433333+00:00

@GitaraniSharma-MSFT , yes that's correct.
GitaraniSharma-MSFT 49,401 Reputation points Microsoft Employee

2024-02-05T14:02:02.98+00:00
@Abhijit Jadhav , apologies for the delay in response.

The "External disconnect due to lost connection" error indicates that the VPN client seems to think that it can no longer contact the gateway.

To troubleshoot this issue further, traces and logs needs to be collected. We would also need to collect the VPN gateway backend logs, so if you have a support plan, I request you file a support ticket, else please do let us know, we will try and help you get a one-time free technical support.

In case you need help with a one-time free technical support, please send an email with subject line "ATTN gishar | P2S connection frequently disconnecting with error [CMMON32]" to AzCommunity[at]Microsoft[dot]com with the following details, I will follow-up with you.

Reference this Q&A thread

Your Azure Subscription ID

Note: Do not share any PII data as a public comment.

We will post a summarized answer once the issue is resolved.

Regards,

Gita

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P2S connection frequently disconnecting with error "[CMMON32] 15:24:00 26 External disconnect due to lost connection"