In staging server hangfire run same job twice

I have created a project on .net core 2.0. In my project there is a requirement i.e

  1. In 11 AM & 5 PM I need to send Mail & Message to user in every day.

  2. I have successfully configure Hangfire in my project & it’s working perfectly in staging server.

My main problem is when the job will run it will send two times mail & message to user.

Can some one help me regarding this?