I don’t think you should be trying to connect to Localhost (127.0.0.1).
First, determine your Guest IP address, then connect using that (typically name resolution is not set up automatically).
You can determine the IP address a number of ways…
Assuming your guest is on a network with a configured DHCP server,
You can run ip addr or on systems that still support you can run ifconifg.
If you have access to the DHCP server that is serving the Guest IP address, you can inpsect issued leases.
Of course, if you didn’t provide a DHCP server on the network your Guest is using, you need to configure a static address.
If this is your situation, you’ll need to provide some additional details about the network your Guest is using.