title: MongoDB returning "Email has already been used" when document is not in collection
body: <p>I am very new to MongoDB and I am testing my register/user route to try to create a new user.  I'm using Postman.  When I try to create the new user, I am getting the error that I set if the user already exists.  However this is a new user and the document is not in the collection.  Please could someone tell me where I am going wrong.</p>
  <pre><code>//Creating a new user
  adminRouter.post('/register/user', async(req, res)=&gt;{
      const {email, password, company, role, firstName, lastName } = req.body;
      console.log('email for new user: ', email);
  
      //check if username already exists
      const takenEmail = await Users.find({email: email});
      
      if (takenEmail) {
          res.status(400).json({message: &quot;Email has already been used&quot;})
      } else {
          const hashedPW = await bcrypt.hash(password,saltRounds);
          await Users.create({
              email: email,
              password: hashedPW,
              company: company,
              role:  role,
              firstName: firstName,
              lastName: lastName,
              
          });
          
          res.json({message: `SUCCESS: User ${email} created.`});
      }
      
  });
  </code></pre>