access the application deployed on Azure Container Instance

As I said in your last question, first of all, you need to make sure the image you used could work well locally. So that it means the image is good to work. Then you need to expose the right port which your application listen to inside the container.

For example, docker image Nginx, it listens to the 80 port, then you need to expose the 80 port when you deploy the image to Azure container instance. And the FQDN has accessed the 80 port in default. If your application listens to 8080 port, and you expose it. Then you need to access your application through the FQDN like this:

testapp.westus.azurecontainer.io:8080

Expose the port in Azure CLI through the parameter --ports:

az container create --resource-group myResourceGroup --name mycontainer --image mcr.microsoft.com/azuredocs/aci-helloworld --dns-name-label aci-demo --ports 80

Expose the port in Azure portal:

Hope it helps. If you have any more questions, please let me know.

Azure Container Instances enables exposing your container groups directly to the internet with an IP address and a fully qualified domain name (FQDN). When you create a container instance, you can specify a custom DNS name label so your application is reachable at customlabel.azureregion.azurecontainer.io.

Azure Container Instances also supports executing a command in a running container by providing an interactive shell to help with application development and troubleshooting. Access takes places over HTTPS, using TLS to secure client connections.

[!IMPORTANT] Starting January 13, 2020, Azure Container Instances will require all secure connections from servers and applications to use TLS 1.2. Support for TLS 1.0 and 1.1 will be retired.