Why can't I access the FTP server from the Internet?

Question

FreeBSD

Good afternoon. We have a Nas4Free file server, there was a need for FTP to it, I turned on FTP configured in services. The port seemed to be opened (it costs kerio). it's not strange that I can log in from the mobile network from the phone, from other places it does not go further than downloading directories, or it says that the password is not correct.
hosts.deny file empty
hosts.allow file:
#ftpd : xxx.xxx.xxx.xxx : deny
#sshd : .example.com : deny
#in.tftpd : xxx.xxx.xxx.xxx : deny
#bsnmpd : xxx. xxx.xxx.xxx : deny
ALL : ALL : allow
ftp
91.202.16.26 port 2121

Answer 1

you should either connect with a client that can work with FTP in passive mode, or configure kerio so that it works correctly with the FTP protocol in active mode (at least add an FTP handler to the FTP rule); Google "FTP over NAT".