AD Integration: No entry found for user when looking up attribute 'sAMAccountName'

I am facing issue in configuring ldap authentication with AD integration and I get error while logging in. Below is my config file.

c.JupyterHub.authenticator_class = 'ldapauthenticator.LDAPAuthenticator'

c.LDAPAuthenticator.server_address = '<ip>'
c.LDAPAuthenticator.server_port = 389
c.LDAPAuthenticator.use_ssl = False
c.LDAPAuthenticator.allowed_groups = []

#set up the template which used to bind the user from ldap directory
#c.LDAPAuthenticator.bind_dn_template = ["uid={username},ou=Admin,ou=Groups,dc=example,dc=com"]

#Active Directory Integration
c.LDAPAuthenticator.lookup_dn = True
c.LDAPAuthenticator.lookup_dn_search_filter = '({login_attr}={login})'
c.LDAPAuthenticator.lookup_dn_search_user = 'user@example.com'
c.LDAPAuthenticator.lookup_dn_search_password = 'redact'
c.LDAPAuthenticator.user_search_base = 'ou=Admin,ou=Groups,dc=example,dc=com'
c.LDAPAuthenticator.user_attribute = 'sAMAccountName'
c.LDAPAuthenticator.lookup_dn_user_dn_attribute = 'cn'
c.LDAPAuthenticator.escape_userdn = False
c.LDAPAuthenticator.bind_dn_template = '{username}'

While logging to jupyterhub with my user I get below error.

[W 2021-03-18 05:02:18.675 JupyterHub ldapauthenticator:275] No entry found for user 'testuser' when looking up attribute 'sAMAccountName'
[W 2021-03-18 05:02:18.675 JupyterHub base:713] Failed login for testuser

versions

python==3.8.5
jupyterhub==1.1.0
jupyterhub-ldapauthenticator==1.3.2

Tried different combinations in configuring the parameters but the error remains the same.
c.LDAPAuthenticator.lookup_dn_search_user is the ldap account that I have mentioned. Is it the correct way?
Any suggestions please.