I cannot add Maven on my Build.Gradle File (I cannot use MotionToast) - Kotlin

Question

I would like to use MotionToast library for my kotlin application but I cannot add this on my build.gradle file;

allprojects {
        repositories {
            ...
            maven { url 'https://jitpack.io' }
        }
    }

It has been given this error;

16:37 Gradle sync failed: Build was configured to prefer settings repositories over project repositories but repository 'maven' was added by build file 'build.gradle' (820 ms)

How can I fix this?