How to configure and troubleshoot Azure load balancer

I create a infrastructure in Azure using following set of "az cli" commands

# Variables
location="eastus"
resourceGroup="nginx-lb-rg"
vnet="nginx-vnet"
subnet="nginx-subnet"
nsg="nginx-nsg"
publicIp="nginx-pubip"
lb="nginx-lb"
lbFrontend="nginx-frontend"
lbBackendPool="nginx-backend-pool"
lbProbe="nginx-health-probe"
lbRule="nginx-http-rule"
vmPrefix="nginx-vm"
adminUser="serveradmin"
adminPassword="5uper5ecureP@ssw0rd"

# Create resource group
az group create --name $resourceGroup --location $location

# Create virtual network and subnet
az network vnet create \
  --resource-group $resourceGroup \
  --name $vnet \
  --address-prefixes "10.0.0.0/16" \
  --subnet-name $subnet \
  --subnet-prefix "10.0.1.0/24"

# Create NSG and allow SSH + HTTP
az network nsg create --resource-group $resourceGroup --name $nsg

az network nsg rule create --resource-group $resourceGroup --nsg-name $nsg \
  --name allow-ssh --priority 100 \
  --direction Inbound --access Allow --protocol Tcp \
  --source-address-prefix '*' --destination-port-range 22

az network nsg rule create --resource-group $resourceGroup --nsg-name $nsg \
  --name allow-http --priority 110 \
  --direction Inbound --access Allow --protocol Tcp \
  --source-address-prefix '*' --destination-port-range 80

# Create public IP
az network public-ip create \
  --resource-group $resourceGroup \
  --name $publicIp \
  --sku Standard \
  --allocation-method Static

# Create Load Balancer
az network lb create \
  --resource-group $resourceGroup \
  --name $lb \
  --sku Standard \
  --frontend-ip-name $lbFrontend \
  --backend-pool-name $lbBackendPool \
  --public-ip-address $publicIp \
  --location $location

# Create health probe
az network lb probe create \
  --resource-group $resourceGroup \
  --lb-name $lb \
  --name $lbProbe \
  --protocol Http \
  --port 80 \
  --path /index.html

# Create load balancing rule
az network lb rule create \
  --resource-group $resourceGroup \
  --lb-name $lb \
  --name $lbRule \
  --protocol Tcp \
  --frontend-port 80 \
  --backend-port 80 \
  --frontend-ip-name $lbFrontend \
  --backend-pool-name $lbBackendPool \
  --probe-name $lbProbe \
  --disable-outbound-snAT true

# Create NICs, associate subnet, NSG, and backend pool
for i in 1 2; do
  nic="${vmPrefix}-nic$i"
  az network nic create \
    --resource-group $resourceGroup \
    --name $nic \
    --vnet-name $vnet \
    --subnet $subnet \
    --network-security-group $nsg

  az network nic ip-config address-pool add \
    --resource-group $resourceGroup \
    --lb-name $lb \
    --address-pool $lbBackendPool \
    --nic-name $nic \
    --ip-config-name ipconfig1
done

# Create Ubuntu VMs with NGINX
for i in 1 2; do
  az vm create \
    --resource-group $resourceGroup \
    --name "${vmPrefix}$i" \
    --image "/subscriptions/8b8fdec4-790a-4019-a7e5-a8b5cb5a3d41/resourceGroups/Azuredevops/providers/Microsoft.Compute/images/PackerImage" \
    --admin-username $adminUser \
    --admin-password $adminPassword \
    --nics "${vmPrefix}-nic$i" \
    --location $location 

done

The Ubuntu image used for VM's is a custom Ubuntu image. All resources got created without any issues. However when I test the URL "http://lb-public-ip/index.html", the URL times out. I connected to each of VM via Bastion and did "curl http://vm-private-ip/index.html" again each VM, that works, so VM's or the image or the local firewalls can be ruled out.

I also checked the NSG rules, the http is allowed and there is no rule denying anything. I also check the HealthProbes, they indicate the backend pool is 100% healthy.

Not sure what am I missing - any hints? - Thanks!