The renewal reminder feature in Procurement > Contracts is limited. The Renewal Reminder sends a notification once the counter reaches your reminder date. After the 60 days, and as you get closer to the Due date, the system doesn't send any notifications.
It would be nice if the system will keep sending notifications until the contract is renewed or deactivated.
Another option is also give the user the ability to custom the "Reminder before date" and not limit it to 120 days as the max.