With my application gateway, I am unable to reach my backend from public network, even though the backend is healthy and listeners are well configured

Question

With my application gateway, I am unable to reach my backend from public network, even though the backend is healthy and listeners are well configured

cargobuddy 20

With my application gateway, I am unable to reach my backend from public network, even though the backend is healthy and listeners are well configured. Here is my configuration:

My AKS cluster is hosted in the same VNET as that of my application gateway (Standard_V2), but in different subnets.
My application gateway is the ingress to my AKS cluster, through AGIC.
The SSL certificate is also configured through key-vault store.
The backend health shows all Ok (green)

However, the services are not reachable through public endpoints.

Praveen Bandaru 11,230 Reputation points Microsoft External Staff Moderator

2026-03-22T06:39:19.4466667+00:00
Hello cargobuddy

I see that your Application Gateway is successfully probing your AKS backend and showing a healthy status, but public internet traffic isn’t passing through. This is usually a network-level issue, often related to NSGs, UDRs, or DNS.

Please provide the following information for further investigation:

Check your NSG and UDR configurations.

Share a screenshot of any errors you see when accessing the Application Gateway URL. Also, try accessing the backend directly from a VM in the same VNET, bypassing the Application Gateway, and share those results.

Check the Application Gateway access logs during the issue and note the status codes for both the gateway and server.

Let me know if this is an existing setup or a new configuration.
cargobuddy 20 Reputation points

2026-03-22T08:58:13.1033333+00:00
Hi,

Please find below the answers:

I see there is no issue with the NSG. However, please suggest if you want me to execute any specific command.

Please find the screenshot below:

Here is my health probe result:

I don't see any logs for my application gateway. Please let me know the place you want me to watch.
cargobuddy 20 Reputation points

2026-03-22T08:58:34.7666667+00:00

Also, this is a completely new deployment.
Praveen Bandaru 11,230 Reputation points Microsoft External Staff Moderator

2026-03-22T09:49:04.5133333+00:00

Hello cargobuddy

I have also initiated a private message. Please check it and provide the necessary information so we can discuss further on your concern. Check the below screen shot to find private message option.

1 answer

Your answer

Praveen Bandaru 11,230 Reputation points Microsoft External Staff Moderator

2026-03-22T06:39:19.4466667+00:00

Hello cargobuddy

I see that your Application Gateway is successfully probing your AKS backend and showing a healthy status, but public internet traffic isn’t passing through. This is usually a network-level issue, often related to NSGs, UDRs, or DNS.

Please provide the following information for further investigation:

Check your NSG and UDR configurations.

Share a screenshot of any errors you see when accessing the Application Gateway URL. Also, try accessing the backend directly from a VM in the same VNET, bypassing the Application Gateway, and share those results.

Check the Application Gateway access logs during the issue and note the status codes for both the gateway and server.

Let me know if this is an existing setup or a new configuration.
cargobuddy 20 Reputation points

2026-03-22T08:58:13.1033333+00:00

Hi,

Please find below the answers:

I see there is no issue with the NSG. However, please suggest if you want me to execute any specific command.

Please find the screenshot below:

Here is my health probe result:

I don't see any logs for my application gateway. Please let me know the place you want me to watch.
cargobuddy 20 Reputation points

2026-03-22T08:58:34.7666667+00:00

Also, this is a completely new deployment.
Praveen Bandaru 11,230 Reputation points Microsoft External Staff Moderator

2026-03-22T09:49:04.5133333+00:00

Hello cargobuddy

I have also initiated a private message. Please check it and provide the necessary information so we can discuss further on your concern. Check the below screen shot to find private message option.

Answer 1

Hello cargobuddy

We have confirmed that your application gateway URL is set up for HTTP traffic. Please check your configuration to ensure both HTTP and HTTPS traffic are allowed.

Also, verify if your backend accepts HTTP traffic. If it does not, update your configuration to use HTTPS. Once that's done, you can configure a certificate in the application gateway and let us know the results.

You can set up a listener with HTTPS in the listener configuration and test it.

I hope the above answer helps you! Please let us know if you have any further questions.

Please don't forget to "upvote" where the information provided will help you, this can be beneficial to other members of the community.

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With my application gateway, I am unable to reach my backend from public network, even though the backend is healthy and listeners are well configured

1 answer

Your answer