Cannot Connect via FTP anymore.

[apinto]

Innovative Tom, thank you for taking the time to provide a detailed report of your errors.

Regarding the proftpd install command it is:

apt-get install proftpd

(eventually with or without sudo depending if oyu are using root or not)
You can also check How To Set Up ProFTPD on Ubuntu (Digital Ocean), the steps should be similar, but actually you are only looking for the install one.

Installing proftpd-basic is normal behavior I think.


Checking if proFTPd is installed
Get a list of all installed packages with the word ftp.

Code:

$ dpkg --get-selections | grep ftp

Expected output is:
ftp                          install
openssh-sftp-server          install
proftpd-basic                install
proftpd-mod-mysql            install

If you see any other packages, remove them (apt-get remove ***), take in consideration this assumes most FTP packages have ftp in the name, if they do not have ftp in the name they will not be listed on the output and oyu need to know what you installed.


The other issue, "unable to resolve..."
This error should not be related to FTP, probably it is related to you hostname.

Check the file /etc/hosts and /etc/hostname you should have the same machine hostname on both files, correct example bellow:

/etc/hosts

Code:

127.0.0.1 pannel.innovativetom.com

Most likely than not, this file will have other entries, do not worry, just make sure it has the correct hostname.

/etc/hostname

Code:

pannel.innovativetom.com