ldapsearch returns Invalid credentials when using a passwdfile

Hello there,

After Configuring LDAP User Stores from the Command Line I like to test the connection with ldapsearch.

When using ldapsearch with the parameter '-W' I was ask for the password, entered it on the command line and got the expected result of my search. Now I put the password into an passwdfile and restricted the file pemissions to read-only access for user root. When I run the search with 'ldapsearch -vvv -h hostname -y passwdfile [...]' and the same parameters from my first search I got the following error:

ldap_initialize( ldap://ldapbackend )
ldap_bind: Invalid credentials (49)

I used VIM to create the passwdfile. It contains nothing else than the password. What is wrong here?

Kind regards,
Joerg K.