Troubleshooting Tip: Unable to backup FortiGate config to external FTP server: 'Send config file to ftp server via vdom root failed. Command fail. Return code 12'

To backup config to the FTP server, use this link:

Technical Tip: Backup of configuration file from CLI using FTP

The issue will be based on this setup:

FortiGate 10.14.2.159 ---- FTP server 10.14.2.116

To backup the config to FTP we run the following command:

execute backup config ftp <filename> <ftp server>[:ftp port] <username> <password>

Follow this KB article is the error code is 12, If the error code is 5:

Troubleshooting Tip: Unable to backup FortiGate config to external FTP server - Send config file to ftp server via vdom root failed. Command fail. Return code 5

Error: 'Send config file to ftp server via vdom root failed. Command fail. Return code 12'

12 FTP_INPUT_ERR Error reading INPUT or STDIN.

Generally, error 12 occurs when the destination folder is not available. Do a packet capture on FortiGate:

diag sniffer packet any 'host <FTP server>' 6 0 l  

Follow:

Technical Tip: How to import 'diagnose sniffer packet' data to WireShark to convert the sniffer output to PCAP.

From GUI:

Go to Network -> Packet capture (upto 7.0.x models) or Network -> Diagnostics (v7.2.x and above). Put a filter for the FTP server IP as the host

Packet capture will show that the directory is not correct:

Visit the FTP server and check the correct file directory to use.

Note:

It is also possible to use Filezilla to list the directory that allows access.