Application crashes on startup (Android Studio)

[Sliccckk]

Hello,

I'm creating (or rather trying to create) an application that is supposed to connect to an automatic greenhouse via bluetooth.
This application works with a database that I created with Firebase.

I also use a repository.

Problem, when I add the lines:
val repo = ProgramRepository()
repo.updateData()

The application opens and closes immediately!
Here is what is marked in the "Run" tab of android studio:

E/AndroidRuntime: FATAL EXCEPTION: main
Process: fr.max.serreconnecte, PID: 3335
java.lang.ExceptionInInitializerError
at fr.max.serreconnecte.ProgramRepository.updateData(ProgramRepository.kt:23)
at fr.max.serreconnecte.MainActivity.onCreate(MainActivity.kt:16)
at android.app.Activity.performCreate(Activity.java:8093)
at android.app.Activity.performCreate(Activity.java:8067)
at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1310)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:3452)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:3651)
at android.app.servertransaction.LaunchActivityItem.execute(LaunchActivityItem.java:85)
at android.app.servertransaction.TransactionExecutor.executeCallbacks(TransactionExecutor.java:135)
at android.app.servertransaction.TransactionExecutor.execute(TransactionExecutor.java:95)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2104)
at android.os.Handler.dispatchMessage(Handler.java:106)
at android.os.Looper.loop(Looper.java:236)
at android.app.ActivityThread.main(ActivityThread.java:7861)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:600)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:967)
Caused by: com.google.firebase.database.DatabaseException: Failed to get FirebaseDatabase instance: Specify DatabaseURL within FirebaseApp or from your getInstance() call.
at com.google.firebase.database.FirebaseDatabase.getInstance(com.google.firebase:firebase-database@@19.2.1:97)
at com.google.firebase.database.FirebaseDatabase.getInstance(com.google.firebase:firebase-database@@19.2.1:57)
at fr.max.serreconnecte.ProgramRepository$Singleton.(ProgramRepository.kt:15)
at fr.max.serreconnecte.ProgramRepository.updateData(ProgramRepository.kt:23) 
at fr.max.serreconnecte.MainActivity.onCreate(MainActivity.kt:16) 
at android.app.Activity.performCreate(Activity.java:8093) 
at android.app.Activity.performCreate(Activity.java:8067) 
at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1310) 
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:3452) 
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:3651) 
at android.app.servertransaction.LaunchActivityItem.execute(LaunchActivityItem.java:85) 
at android.app.servertransaction.TransactionExecutor.executeCallbacks(TransactionExecutor.java:135) 
at android.app.servertransaction.TransactionExecutor.execute(TransactionExecutor.java:95) 
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2104) 
at android.os.Handler.dispatchMessage(Handler.java:106) 
at android.os.Looper.loop(Looper.java:236) 
at android.app.ActivityThread.main(ActivityThread.java:7861) 
at java.lang.reflect.Method.invoke(Native Method) 
at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:600) 
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:967) 

I didn't find any answer on the forums
Help would be greatly appreciated.
Thanks in advance