Problem with the discount module

[kportal]

Ladies and Gentlemen!

I have the following problem with PrestaShop. I will not hide the fact that I work practically on WordPress, but I received a task from my client to properly set up his website/store which is based on PrestaShop.

The problem is that the client has a store with rental products for occasions, e.g. weddings, based on the installed calendar, the second plugin which is "rental_rabats" is supposed to calculate a specific discount based on days, e.g. for 3 days it is 20%.

I set everything in the rental_rabats files according to the client table and nothing works at all. All the time some errors pop up in the logs, in the database the module writes that it is enabled, in the PrestaShop store in the settings it writes that it is enabled.

And I receive this message on the side of the server where the domain is located in the logs:

[07-Jul-2025 23:06:44 Europe/Warsaw] RENTAL DEBUG - Action: remove_rental_from_cart
[07-Jul-2025 23:06:52 Europe/Warsaw] RENTAL DEBUG - Action: getRentalDates
[07-Jul-2025 23:06:52 Europe/Warsaw] RENTAL DEBUG - getRentalDates - Cart ID: 24376
[07-Jul-2025 23:06:55 Europe/Warsaw] === RENTALCART AJAX: addToCartWithRental started ===
[07-Jul-2025 23:06:55 Europe/Warsaw] RENTALCART AJAX: Product ID: 198, Dates: 2025-07-08 to 2025-07-18, Qty: 1
[07-Jul-2025 23:06:55 Europe/Warsaw] RENTALCART AJAX: Cart updateQty result: true
[07-Jul-2025 23:06:55 Europe/Warsaw] RENTALCART AJAX: saveRentalDates result: success
[07-Jul-2025 23:06:55 Europe/Warsaw] RENTALCART AJAX: Attempting to get rental_rabats module instance.
[07-Jul-2025 23:06:55 Europe/Warsaw] RENTALCART AJAX: rental_rabats module instance received. Active status: false
[07-Jul-2025 23:06:55 Europe/Warsaw] ERROR RENTALCART AJAX: rental_rabats module found but NOT ACTIVE.
[07-Jul-2025 23:06:55 Europe/Warsaw] RENTALCART AJAX: SUCCESS: Sending response.
[07-Jul-2025 23:06:59 Europe/Warsaw] RENTAL DEBUG - Action: remove_rental_from_cart

It's as if PrestaShop didn't read the module at all, despite it being enabled, which is confirmed by the database and enabled in the admin login to PrestaShop.

Additionally, " Module::getInstanceByName() " pops up, I don't know what it's about, and I've been working on this problem for about 20 working hours and the client won't talk to me. I have already asked Gemini about this problem and tried to solve it with them but it didn't help and the problem is still the same.

Or is there a free plugin that I could replace "rental_rabats" that would work more or less on the same principle?

It's really annoying for me and the client is also pressed for time. I should add that the client uses the WareHouse theme.