I'm trying to add an organization with ldapadd command and I keep getting Inappropriate authentication (48) error.

My command -

ldapadd -x -D "cn=Directory Administrators,dc=mit,dc=example,dc=com" -W  -f my_org.ldif

This is what I get -

Enter LDAP Password: 

ldap_bind: Inappropriate authentication (48)

This is my ldif file - my_org.ldif

dn: cn=em,dc=mit,dc=example,dc=com

ou: em

objectClass: top

objectclass: organizationalunit

This is my output for

 ldapsearch -x -w -D 'cn=Directory Administrators,dc=mit,dc=example,dc=com' -b 'dc=mit,dc=example,dc=com' '(objectclass=*)'

# extended LDIF
#
# LDAPv3
# base  with scope subtree
# filter: cn=Directory Administrators,dc=mit,dc=example,dc=com
# requesting: (objectclass=*) 
#

# search result
search: 2
result: 0 Success

# numResponses: 1