about ftp server in linux
 

i have installed a ftp server with user login id and password but when i connect to my server by using browser it gives an error 550 failed to change directory what can i do for that .

No idea..since you give us no details.

What version/distro of Linux? Which FTP server? What network environment (local? WAN? Internet?). Was it ever working? Using anonymous ID or a 'real' user id? Virtual user or 'real' user?

If you put that error into Google, you'll find LOTS of potential solutions...and if you even tried searching THIS site, you'd find them too:
https://www.linuxquestions.org/quest...problem-61646/
https://www.linuxquestions.org/quest...vsftpd-922686/
https://www.linuxquestions.org/quest...denied-814508/
https://www.linuxquestions.org/quest...upload-786158/