App not running in device with the minSdkVersion required

Question

I just finished an Android app I have been building and so far every test has worked fine. I was testing the app in emulators with API 29 and with Android 10. Now I am doing more testing in more APIs that the app should support, the minSdkVersion is 26, which is Android 8.0, and works great in devices with API 29, 28 and 27 but with 26 does not work, even though supposedly it should work.

This is the Logcat message

2020-02-17 00:05:53.040 5863-5863/com.Interactive.textmefriends E/AndroidRuntime: FATAL EXCEPTION: main
Process: com.Interactive.textmefriends, PID: 5863
java.lang.RuntimeException: Unable to get provider com.google.firebase.provider.FirebaseInitProvider: java.lang.ClassNotFoundException: Didn't find class "com.google.firebase.provider.FirebaseInitProvider" on path: DexPathList[[zip file "/data/app/com.Interactive.textmefriends-vAS2vg-yDZ7Lakv7e5ZzJA==/base.apk"],nativeLibraryDirectories=[/data/app/com.Interactive.textmefriends-vAS2vg-yDZ7Lakv7e5ZzJA==/lib/x86, /system/lib, /vendor/lib]]
    at android.app.ActivityThread.installProvider(ActivityThread.java:6288)
    at android.app.ActivityThread.installContentProviders(ActivityThread.java:5851)
    at android.app.ActivityThread.handleBindApplication(ActivityThread.java:5772)
    at android.app.ActivityThread.-wrap1(Unknown Source:0)
    at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1661)
    at android.os.Handler.dispatchMessage(Handler.java:105)
    at android.os.Looper.loop(Looper.java:164)
    at android.app.ActivityThread.main(ActivityThread.java:6541)
    at java.lang.reflect.Method.invoke(Native Method)
    at com.android.internal.os.Zygote$MethodAndArgsCaller.run(Zygote.java:240)
    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:767)
 Caused by: java.lang.ClassNotFoundException: Didn't find class "com.google.firebase.provider.FirebaseInitProvider" on path: DexPathList[[zip file "/data/app/com.Interactive.textmefriends-vAS2vg-yDZ7Lakv7e5ZzJA==/base.apk"],nativeLibraryDirectories=[/data/app/com.Interactive.textmefriends-vAS2vg-yDZ7Lakv7e5ZzJA==/lib/x86, /system/lib, /vendor/lib]]
    at dalvik.system.BaseDexClassLoader.findClass(BaseDexClassLoader.java:93)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:379)
    at java.lang.ClassLoader.loadClass(ClassLoader.java:312)
    at android.app.ActivityThread.installProvider(ActivityThread.java:6273)
    at android.app.ActivityThread.installContentProviders(ActivityThread.java:5851) 
    at android.app.ActivityThread.handleBindApplication(ActivityThread.java:5772) 
    at android.app.ActivityThread.-wrap1(Unknown Source:0) 
    at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1661) 
    at android.os.Handler.dispatchMessage(Handler.java:105) 
    at android.os.Looper.loop(Looper.java:164) 
    at android.app.ActivityThread.main(ActivityThread.java:6541) 
    at java.lang.reflect.Method.invoke(Native Method) 
    at com.android.internal.os.Zygote$MethodAndArgsCaller.run(Zygote.java:240) 
    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:767)