Start with basic troubleshooting. RDP to the VM and from a Powershell prompt run Test-Netconnection and Invoke-WebRequest to the site name and see if you get any response back. If you get a 404 or unauthorized error, then you at least know that a firewall isn't blocking the port. Then run the same test from some other non-Azure machine and see if you get the same results.
PS C:\> (Invoke-WebRequest https://www.yahoo.com).StatusCode
200
PS C:\> Test-NetConnection www.yahoo.com -port 443 ComputerName : www.yahoo.com RemoteAddress : 74.6.143.25 RemotePort : 443 InterfaceAlias : Wi-Fi
SourceAddress : 192.168.1.6
TcpTestSucceeded : True