I can't see the required files in required directories

I am getting successful build in ftp server as :

ftp> put ~/workspace/ftp_client/upload.txt
local: /home/crio-user/workspace/ftp_client/upload.txt remote: /home/crio-user/workspace/ftp_client/upload.txt
200 PORT command successful. Consider using PASV.
550 Permission denied.
ftp> pwd
257 "/home/crio-user/workspace/ftp_server" is the current directory
ftp> cd ~/workspace/ftp_client
250 Directory successfully changed.
ftp> get ~/workspace/ftp_server/download.txt
local: /home/crio-user/workspace/ftp_server/download.txt remote: ~/workspace/ftp_server/download.txt
200 PORT command successful. Consider using PASV.
150 Opening BINARY mode data connection for /home/crio-user/workspace/ftp_server/download.txt (40 bytes).
226 Transfer complete.
40 bytes received in 0.01 secs (2.7229 kB/s)

while I can’t browse files in my workspace. Is everything correct?

crio-user@dashnabanita:~/workspace/ftp_client$ ls
upload.txt
crio-user@dashnabanita:~/workspace/ftp_client$ cd ..
crio-user@dashnabanita:~/workspace$ cd ftp_server
crio-user@dashnabanita:~/workspace/ftp_server$ ls
download.txt
crio-user@dashnabanita:~/workspace/ftp_server$ ls -a
.  ..  download.txt