Duplicate mails are sent to the user

I have a scheduled agent that sends reminder to the user on the day of the month configured.The scheduled agent property is :

Schedule - Daily

Target - All new & modified documents

Run agent once every day:

Start running agent at 1AM

The issue is that on the configured day , the user has received 3 reminder mails (Duplicate mails)

Can anyone help me?

Subject: RE: Duplicate mails are sent to the user

Can anyone help me to solve the issue?