I can't connect to my host using FileZilla/FTP; Authentication failed, Could not connect to server

We’re definitely happy to get you moving in the right direction.

The first thing you should figure out is whether you’re using FTP or SFTP with FileZilla. By default, FTP doesn’t use any encryption and runs over port 21. SFTP uses SSH protocol, contains security features not found with FTP, and runs over your SSH port (typically port 22). I’d recommend sticking with SFTP because of these security features. That said, if the port you’re trying to use is closed, it could definitely cause the error message you’re seeing. You can check the status of these ports with nmap:

nmap -p 21,22 <IP>

Because SFTP is part of the SSH service that’s already built into your Linode, your login credentials will be the same as SSH. If you need help connecting via SSH, we have a guide that walks you through the process:

Connect to Your Linode via SSH

If you’re not sure what your user login credentials are, you can reset them by logging in as the root user via SHH or Lish. If you’re unsure of your root password, you can reset that from the Linode Cloud Manager by following this guide.

You can also try running some of the following commands if you’re still experiencing connection issues. These will look at your SSH configuration (using the egrep command from your Linode), check your SSH port (with the netstat command from your Linode), and view any specific connection issues (with the verbose SSH command while connecting from your local machine).

egrep -i '(password|permit|port|pubkey)' /etc/ssh/sshd_config

netstat -tulpn

ssh -vvv user@hostname

Otherwise, if you happen to be using FTP rather than SFTP, I found some useful documentation from Ubuntu about configuring your FTP server and users:

Ubuntu Documentation: FTP Server

Hope this helps!