a few contracts sent notification email twice every day(the reminder notification was set 90, 60, 30 days before), 

and I create two sample contracts in application

1.Contract Name: test

  Contract ID: test-0001

  Active period: 2019.10.18-2019.10.22

  Reminder Notification: 3 days and 1 day before(still don't receive any notification email for this contract)

2.Contract Name: test2

  Contract ID: test-0002

  Active period: 2019.10.21-2019.10.26

  Reminder Notification: 3 days and 1 day before