Not Sending automatic email when deployed on IIS on Remote server

There was an error during processing of the managed application service auto-start for configuration path: 'MACHINE/WEBROOT/APPHOST/ …

Exception: System.InvalidOperationException

Message: An error occurred while trying to create preload provider…

Exception: System.IO.FileNotFoundException

Message: Could not load file or assembly ‘HangFireEx’ or one of its dependencies. The system cannot find the file specified.