Virtualbox, ssh from Ubuntu host to Ubuntu guest: connection refused

I'm trying to connect to my virtual machine and I'm continously getting the following error:

ssh: connect to host 192.168.56.101 port 22: Connection refused

My host OS is a fresh installed Ubuntu 18.04 and the virtual machine is an old Ubuntu 14.04 (the virtual machine isn't a fresh install; rather, I've created a new virtual machine and then import the virtual hard disk file .dvi from my old laptop where sshing worked without issues).

I can ping to the machine without package loss, and I think everything is correctly configured.

On the virtual machine, I have two adapters, the defaulted NAT, without any port forwarding rule, and the usual vboxnet0 Host-only adapter. Such vboxnet0 host-only adapter has been created by going to File -> Host Network Manager, and adding a new entry. The DHCP server is disabled, and the IP address/mask is 192.168.56.101/24:

The ifconfig output from my virtual machine is:

and that's the contents of its /etc/network/interfaces:

The ifconfig output from my Host machine is:

enp61s0: flags=4099<UP,BROADCAST,MULTICAST>  mtu 1500
        ether 00:d8:61:06:78:ce  txqueuelen 1000  (Ethernet)
        RX packets 0  bytes 0 (0.0 B)
        RX errors 0  dropped 0  overruns 0  frame 0
        TX packets 0  bytes 0 (0.0 B)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0
        device interrupt 16  

lo: flags=73<UP,LOOPBACK,RUNNING>  mtu 65536
        inet 127.0.0.1  netmask 255.0.0.0
        inet6 ::1  prefixlen 128  scopeid 0x10<host>
        loop  txqueuelen 1000  (Local Loopback)
        RX packets 2430  bytes 204819 (204.8 KB)
        RX errors 0  dropped 0  overruns 0  frame 0
        TX packets 2430  bytes 204819 (204.8 KB)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0

vboxnet0: flags=4163<UP,BROADCAST,RUNNING,MULTICAST>  mtu 1500
        inet 192.168.56.101  netmask 255.255.255.0  broadcast 192.168.56.255
        inet6 fe80::800:27ff:fe00:0  prefixlen 64  scopeid 0x20<link>
        ether 0a:00:27:00:00:00  txqueuelen 1000  (Ethernet)
        RX packets 0  bytes 0 (0.0 B)
        RX errors 0  dropped 0  overruns 0  frame 0
        TX packets 225  bytes 35362 (35.3 KB)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0

wlo1: flags=4163<UP,BROADCAST,RUNNING,MULTICAST>  mtu 1500
        inet 10.181.127.144  netmask 255.255.0.0  broadcast 10.181.255.255
        inet6 fe80::e7bf:1f7f:8578:e980  prefixlen 64  scopeid 0x20<link>
        ether 98:3b:8f:d8:06:17  txqueuelen 1000  (Ethernet)
        RX packets 90490  bytes 44130738 (44.1 MB)
        RX errors 0  dropped 0  overruns 0  frame 0
        TX packets 15323  bytes 2985782 (2.9 MB)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0

and its etc/network/interfaces is the default one:

# interfaces(5) file used by ifup(8) and ifdown(8)
auto lo
iface lo inet loopback

In the virtual machine, the ssh server is in start/running state and ufw is not blocking port 22:

However, from my host machine:

$ ssh -vvv 192.168.56.101
OpenSSH_7.6p1 Ubuntu-4ubuntu0.3, OpenSSL 1.0.2n  7 Dec 2017
debug1: Reading configuration data /etc/ssh/ssh_config
debug1: /etc/ssh/ssh_config line 19: Applying options for *
debug2: resolving "192.168.56.101" port 22
debug2: ssh_connect_direct: needpriv 0
debug1: Connecting to 192.168.56.101 [192.168.56.101] port 22.
debug1: connect to address 192.168.56.101 port 22: Connection refused
ssh: connect to host 192.168.56.101 port 22: Connection refused

NOTE: Adding a port forwarding rule to the NAT adapter, unless I did it wrong, didn't solved the issue; besides, in my old laptop I have no port forwarding rules.