Connection is always refused by Ubuntu in a Virtual Machine (Hyper-V)

Hi, I'm new, I watched so many YouTube Tutorials but they just enter the IP address without explaining how did they get it.

Host name:
I tried to intentionally fake the IP address, for example 172.25.160.66 instead of 172.25.160.65 then the result is "Network error: Connection time out" instead of refused, which means that the IP address exists but just refused.

Username and password:
People say that the default username and password of Ubuntu are nothing, so I just type nothing for them.

WinSCP: Version 5.19.1 (Build 11552)

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Step 1 - Enable connection
https://askubuntu.com/questions/890763/connection-to-ftp-always-refused

# Backup the current configuration file. (optional)
sudo mv /etc/vsftpd.conf /etc/vsftpd.backup
 
# Uninstall vsftpd and purge the configuration files.
sudo apt-get remove --purge vsftpd
 
# Lastly, re-install vsftpd.
sudo apt-get install vsftpd
 
# Test
ftp -p x.x.x.x

The default password for the user 'ubuntu' on Ubuntu is blank.

Step 2 - Permission to edit the file /etc/vsftpd.conf
https://askubuntu.com/questions/150028/you-are-not-the-owner-message-when-trying-to-access-folder

sudo chown -R username /path/to/directory

Example:
Step 3 - Enable writing
https://askubuntu.com/questions/410947/permission-denied-in-ftp-even-though-im-the-owner

In the file "/etc/vsftpd.conf", uncomment the line

#write_enable=YES

Important:
Watch this video how to change the file permission in Terminal instead of using a Text Editor:
https://www.youtube.com/watch?v=qpt5mxVVJoE

sudo su
vi /etc/vsftpd.conf
 
ESCAPE :wq (to exit)

Save the file and restart vsftpd with sudo service vsftpd restart