title: Current topology does not support session
body: <p><a href="https://i.stack.imgur.com/cOCtE.png" rel="noreferrer"><img src="https://i.stack.imgur.com/cOCtE.png" alt="enter image description here"></a></p>
  
  <p>Hi,</p>
  
  <p>I am getting error "<strong>Current topology does not support session</strong>"
  Plese refer attached image..</p>
  
  <p>and code as </p>
  
  <pre><code>async function insertBooking(parking, aFunction) {
      const session = await BookingSchema.startSession().catch(error =&gt; {
          console.log(error);
      });
  
      try {
          session.startTransaction();
          let booking = new BookingSchema(parking)
          mongoose.startSession();
          booking.save(function (err, booking) {
              if (booking) {
                 //code to be run
              }
  
  
          })
          await session.commitTransaction().catch(error =&gt; {
              console.log(error);
          });
          session.endSession()
      } catch (error) {
          await session.abortTransaction().catch(error =&gt; {
              console.log(error);
          });
          session.endSession();
          throw error;
      }
  }
  </code></pre>
  
  <p>Above code completely work on local system.
  but erro occure on cloud server (Digital ocean) 
  Please let me know if another information needed.</p>