IOS15 not showing ATT prompt using applicationDidBecomeActive

Hey guys, recently my proyect stop showing the ATT prompt and I cant find where is the problem when it worked perfect before. Previously I was using didFinishLaunchingWithOptions but i saw some post where said that was the problem and some solve the problem by changing to applicationDidBecomeActive. This is my current AppDelegate.m

#import "AppDelegate.h"
#import "MainViewController.h"
#import <AppTrackingTransparency/AppTrackingTransparency.h>
@implementation AppDelegate
- (void)applicationDidBecomeActive(UIApplication*)application
{
    self.viewController = [[MainViewController alloc] init];
    if (@available(iOS 14, *)) {
        [ATTrackingManager requestTrackingAuthorizationWithCompletionHandler:^(ATTrackingManagerAuthorizationStatus status) {
            //If you want to do something with the pop-up
        }];
    }
}@end

While pre IOS 15 this code worked

#import "AppDelegate.h"
#import "MainViewController.h"
#import <AppTrackingTransparency/AppTrackingTransparency.h>

@implementation AppDelegate

- (BOOL)application:(UIApplication*)application didFinishLaunchingWithOptions:(NSDictionary*)launchOptions
{
    self.viewController = [[MainViewController alloc] init];
    if (@available(iOS 14, *)) {
        [ATTrackingManager requestTrackingAuthorizationWithCompletionHandler:^(ATTrackingManagerAuthorizationStatus status) {
            //If you want to do something with the pop-up
        }];
    }
    return [super application:application didFinishLaunchingWithOptions:launchOptions];
}

@end

I dont really know why the event is not getting triggered. Best regards.