Android Multi Dex Debug

When your Android App’s minSdkVersion is prior to 21(using dalvik), and your app and the libraries it references exceed 65,536 methods, Android studio debugger does not work otherwise your expectation, silently. Of course, it is not that all break points do not work. Some Activity Classes can trigger debugger. But Almost any other break points in java classes & kotlin classes would betray you.

I couldn’t know the cause exactly. However Multiple DEX problem might affect it. So believe me, upgrade minSdkVersion to 21 or higher and using ART. ART natively supports loading multiple DEX files. If using ART is impossible, add multidex support lirary to your project

You can find library version in this page

dependencies {
    // Using AndroidX
    // If you're not using AndroidX, find other support library
    implementation 'androidx.multidex:multidex:2.0.1'
}

Reference: Enable multidex for apps with over 64K methods