i have an issue in email scheduling in web application

Question

I have an issue in email scheduling in web application. I scheduled email for user with frequency of 2 days but its not working properly.  It was delivered successfuly on the same day i scheduled but it is not delivered thereafter. (for ex. I scheduled email on 07/11/2019 Effective from 07/12/2019 1:30pm and Effective to 31/12/2019 then its send successfuly on 07/11/2019 but it is not delivered after 07/11/2019 )