DNS – DNS – DNS
Skipping past the questions about what type of server, what type of client, what browser, what web server which would have made a definitive answer easier.
When you ‘browse’ (try to make an internet connection) there are three interfaces involved – you to the computer, the computer to the network, and the network to the router/switch (potentially many routers). In reverse order – the network to/from router/switch only knows numbers (IP addresses) take packets from this port and pass them to another port based on address. To achieve the number we pass names to a ‘Name Server’ [Domain Name Service]. When you type a name in the browser it asks the computer ‘Do You know where this is?’. If the answer is no then the computer asks the router/switch to pass the message to one of the DNS servers for an answer. You or DHCP saved the addresses of one or more DNS units when you set up networking. Try to ping the web server by name and see if the address is resolved, If not then ping by ip address (numbers) and if that doesn’t work you are being blocked by firewall.