python TypeError: Object of type ndarray is not JSON serializable

@app.route('/nodes/resolve', methods=['GET'])
def consensus():
    replaced = blockchain.resolve_conflicts()

    if replaced:
        response = {
            'message': 'Our chain was replaced',
            'new_chain': blockchain.chain
        }
    else:
        response = {
            'message': 'Our chain is authoritative',
            'chain': blockchain.chain
        }

    return jsonify(response), 200

resolve_conflicts function :

def resolve_conflicts(self):
        neighbours = self.nodes
        new_chain = None
        max_length = len(self.chain)
        for node in neighbours:
            response = requests.get(f'http://{node}/chain')
            if response.status_code == 200:
                length = response.json()['length']
                chain = response.json()['chain']
                if length > max_length and self.valid_chain(chain):
                    max_length = length
                    new_chain = chain
        if new_chain:
            self.chain = new_chain
            return True
        return False

when i run "curl http://localhost:5000/nodes/resolve" in cmd, but it is throwing below error:

TypeError: Object of type ndarray is not JSON serializable