If your work on AIX System (or any other UNIX/Linux Distribution), may be you face the following Message when you try to access SFTP:

Couldn't canonicalise: Permission denied
Need cwd

after many troubleshooting :
– user can access SSH without any problem.
– user can’t access SFTP
– you can switch on this user normally.

after analysis the problem and search on the internet (reference is below), we found that:
the user which we try to connect SFTP using it, his home directory is a file system ( which is normal ) & we found that the file system owned by this user (which is also normal) but the base directory (the normal directory after umount the file system) with a different permissions.

now the Technical Steps:

#sftp user1@10.40.40.60
user1@10.40.40.60's password:
Connected to 10.40.40.60.
Couldn't canonicalise: Permission denied
Need cwd

#ls -ld /user1
drwxr-xr-x   13 user1   usergroup          4096 Jan 10 08:17 /user1
#umount /user1
#ls -ld /user1
drwxr-x---    2 202      204             256 Apr 11 2015  /user1
#chown user1:usergroup /user1
#ls -ld /user1
drwxr-x---    2 user1   usergroup           256 Apr 11 2015  /user1
#mount /user1
#ls -ld /user1
drwxr-xr-x   13 user1   usergroup          4096 Jan 10 08:17 /user1