ftp connection error on command line

500 I won't open a connection to 172.31.xx.xxx (only to 19.216.xxx.xxx)ftp: bind: Address already in use

If you are trying to make a connection to ftp on command line and you are getting above error, it means ftp is trying to connect to the server using private IP but it cannot connect to remote server using private IP as it needs public IP. You have already passed public IP but still it is connecting to private IP and showing error 500. Here is solution for you.

Soluton :

Connect to ftp server in passive mode using -p

ftp -p ftp.domainname
or
ftp -p 19.216.xxx.xxx

It will ask username and password and after typing it, you should be able to connect to remote server successfully.