Run CountDownTimer inside CoroutineWorker

I am developing a registration form with kotlin in android and after several failed attempts I need to block the form for a while, be it an hour or 30 minutes and that the service runs in the background so the app closes or destroys

After consulting and reading the android documentation, I am solving this problem with workmanager by extending the CoroutineWorker() class, but I find the following problem that does not let me proceed:

Can't create handler inside thread Thread[DefaultDispatcher-worker-1,5,main] that has not called Looper.prepare()

ViewModel that invokes the CoroutineWorker

    @HiltViewModel
class RegisterViewModel @Inject constructor(
    private val registerUseCase: RegisterUseCase
) : ViewModel() {
	
		fun makeApiPost(
				context: Context,
				card: String,
				.... : ...
			)
		{

			viewModelScope.launch {
				val retroInstance = RetroInstance.getRetroInstanceAuth(context).create(
					RetroService::class.java
				)
				val call = retroInstance.getGiftCardBalance(
					CardBalanceRequest(card, ..., ...)
				)
				call.enqueue(object : Callback<BalanceResponse> {
					override fun onResponse(
						call: Call<BalanceResponse>,
						response: Response<AppBalanceResponse>
					) {

						if (response.isSuccessful) {
							val destination = response.body()
							destination?.let {
								_cardBalance.postValue(response.body()!!.payload.data)
							}
						} else {

							val workManager = WorkManager.getInstance(ExtendedApp.myContext)
							workManager.enqueue(OneTimeWorkRequest.from(WorkerActivate::class.java))

							_cardBalance.postValue(null)
						}

					}

					override fun onFailure(call: Call<CardBalanceResponse>, t: Throwable) {
						t.printStackTrace()
						_cardBalance.postValue(null)
						call.request()
					}
				})
			}
		}
}

Background process

    class WorkerActivate(context: Context, workerParameters: WorkerParameters) : CoroutineWorker(
        context, workerParameters
    )
    {
    
        lateinit var countDownTimer: CountDownTimer
    
        override suspend fun doWork(): Result {
    		
            val minutesTimer: Long =  (60 * 1000 * 30)

    		countDownTimer =  object : CountDownTimer(minutesTimer, 1000){
    			override fun onTick(millisUntilFinished: Long) {
    				Log.d("card", "Counting Down: ${millisUntilFinished/1000}")
    			}
    
    			override fun onFinish() {
    				Log.i("card", "countDownTimer de 15 segundos ok")
    			}
    		}
    		
    		return Result.success()
    		
    	}
    }

in your code 13 line is the problem. WorkManager can only be started from the Main thread and that`s the reason you are getting this error.

viewModelScope.launch {
<<< This area is sub Thread >>>
}

// Try this...
withContext(Dispatchers.Main) {
    val workManager = WorkManager.getInstance(ExtendedApp.myContext)
    workManager.enqueue(OneTimeWorkRequest.from(WorkerActivate::class.java))
}