Could be several issues. Here are some steps to try to work through them. Hopefully one of these helps.
- Verify that the public IP address is correct: Make sure that you are using the correct public IP address to connect to the firewall. You can check the public IP address of the firewall in the Azure portal under the "Public IP addresses".
- Check the firewall rules: Verify that the firewall rules are set up correctly to allow traffic to pass through the firewall. You can check the rules in the Azure portal under the "Firewall rules" .
- Check the network security group (NSG) rules: Make sure that the NSG rules are not blocking traffic to the firewall. You can check the NSG rules in the Azure portal under the "Network security groups".
- Check the virtual network configuration: Verify that the virtual network configuration is set up correctly and that the firewall is associated with the correct virtual network. You can check the virtual network configuration in the Azure portal under the "Virtual networks".
- Check the routing: Verify that the routing is set up correctly and that the traffic is being routed to the correct subnet. You can check the routing in the Azure portal under the "Route tables".
- Check the DNS settings: Make sure that the DNS settings are configured correctly to resolve the public IP address to the correct firewall endpoint. You can check the DNS settings in the Azure portal under the "DNS zones".