SharePoint Workflow Send Email activity not works and throws error occured in workflow

If you recieve a error while testing custom workflow when the “Send Email” activity executes,even though your content type supports sending email and your out-going email settings are correct. It should be 100 out of 99 times due to the mistake you would have done during the time of building the custom workflow,just go the project open your workflow in design mode,select the “Send Email” activity wherever available and check whether the “Correlation Token” is set to the default “workflowToken“,if it is set to your custom token please change it to”workflowToken“

 

Enjoy..