anonymous error in nodejs mongodb

Guys I am facing the below irrelevant error.

500 Error: Argument passed in must be a single String of 12 bytes or a string of 24 hex characters
at Function.createFromHexString (/home/r121/Desktop/nilesh/cmarin-MongoDB-Node-Express-Blog-4a5e5e9/trucy-mongodb-express-node.js-blog-37daddd/node_modules/mongodb/node_modules/bson/lib/bson/objectid.js:214:11)
at ArticleProvider.findById (/home/r121/Desktop/nilesh/cmarin-MongoDB-Node-Express-Blog-4a5e5e9/trucy-mongodb-express-node.js-blog-37daddd/articleprovider-mongodb.js:61:89)
at ArticleProvider.getCollection (/home/r121/Desktop/nilesh/cmarin-MongoDB-Node-Express-Blog-4a5e5e9/trucy-mongodb-express-node.js-blog-37daddd/articleprovider-mongodb.js:39:10)
at Db.collection (/home/r121/Desktop/nilesh/cmarin-MongoDB-Node-Express-Blog-4a5e5e9/trucy-mongodb-express-node.js-blog-37daddd/node_modules/mongodb/lib/mongodb/db.js:478:44)
at ArticleProvider.getCollection (/home/r121/Desktop/nilesh/cmarin-MongoDB-Node-Express-Blog-4a5e5e9/trucy-mongodb-express-node.js-blog-37daddd/articleprovider-mongodb.js:37:11)
at ArticleProvider.findById (/home/r121/Desktop/nilesh/cmarin-MongoDB-Node-Express-Blog-4a5e5e9/trucy-mongodb-express-node.js-blog-37daddd/articleprovider-mongodb.js:58:10)
at /home/r121/Desktop/nilesh/cmarin-MongoDB-Node-Express-Blog-4a5e5e9/trucy-mongodb-express-node.js-blog-37daddd/app.js:63:21
at callbacks (/home/r121/Desktop/nilesh/cmarin-MongoDB-Node-Express-Blog-4a5e5e9/node_modules/express/lib/router/index.js:272:11)
at param (/home/r121/Desktop/nilesh/cmarin-MongoDB-Node-Express-Blog-4a5e5e9/node_modules/express/lib/router/index.js:246:11)
at param (/home/r121/Desktop/nilesh/cmarin-MongoDB-Node-Express-Blog-4a5e5e9/node_modules/express/lib/router/index.js:243:11)

While I am just calling the /blog/search method which looks like this

app.get('/blog/search', function(req, res) {

        res.render('blog_search.ejs', {
            title: 'Search Contact',
            });
                 });

My blog_search.ejs looks like this

<h1><%= title %></h1>
   <form method="post" action="/blog/search">
     <input type="text" name="title">
     <input type="submit" name="submit">

Please help me out with this error.I get this error while accessing it with the URL as well as the a href.