Not able to send signed request to authentik from django project using djangosaml2

Question

[DJangoSAML2][1]
Here is the SAML configuration in settings.py file

SAML_CONFIG = {
    'xmlsec_binary': '/usr/bin/xmlsec1',
    'name': 'authentik',
    'entityid': 'authentik',
    'service': {
        'sp': {
            'want_assertions_signed': True,
            'want_response_signed': True,
            'allow_unsolicited': True,
            'endpoints': {
                'assertion_consumer_service': [
                    ('http://localhost:8003/saml/acs/', saml2.BINDING_HTTP_POST),
                ],
                'single_logout_service': [
                    ('http://localhost:8003/saml/ls/', saml2.BINDING_HTTP_REDIRECT),
                ],
            },
            'required_attributes': ['email'],
            'assertionConsumerService': {
                'url': 'localhost:8003/admins/message/',  # URL to receive SAML responses
                # Use the Redirect binding
                'binding': 'urn:oasis:names:tc:SAML:2.0:bindings:HTTP-Redirect',
            },
        },
    },
    'debug': 1,
    # private part(downloaded from authentik)
    'key_file': os.path.join(BASE_DIR, 'authentik_private_key.pem'),
    # public part(downloaded from authentik)
    'cert_file': os.path.join(BASE_DIR, 'authentik_certificate.pem'),
    'allow_unknown_attributes': True,
    # 'attribute_map_dir': os.path.join(BASE_DIR, 'authentik/attribute_maps'),
    'metadata': {
        'local': [os.path.join(BASE_DIR, 'SAML-admin_authentik_meta.xml')],
    },
    'valid_for': 24,  # how long is our metadata valid
    'accepted_time_diff': 120,  # seconds
}

I am getting Verification Certificate configured, but request is not signed. error when want_assertions_signed and want_response_signed is set to True.

Am I missing some configuration in the settings file.Why the request is not getting signed using this configurations.

Any leads will be helpful.