How to display data from mongoDB in html by express.js

Question

I'm new in development and I try to make an authorisation in my test site. Everything is okay in server's part, I can create a user and then login to it, but when I want to display information of the user, my program nothing, but also this message: "Handlebars: Access has been denied to resolve the property "username" because it is not an "own property" of its parent."

Please, tell me, what am I doing wrong?

Login function:

async login(req, res){
        try {
            const {username, password} = req.body;
            const user = await User.findOne({username: username});
            

            if(!user){
                return res.status(400).json({message: ''});
            }
            const validPassword = bcrypt.compareSync(password, user.password);
            if(!validPassword){
                return res.status(400).json({message: ''});
            }

            const token = generateAccessToken(user._id, user.roles);
            res.render('myPage',{
                title: 'list',
                user
            });
            
            
        } catch(e) {
            console.log(e);
            res.status(400).json({message: 'Server Error'});
        }
    }

HTML:

<div class="container">
    {{#if user}}
        <p> {{this.user.username}} </p>

    {{else}}
        
        <p>Error</p>
    {{/if}}
</div>