How to solve 'Can not access class “ViewModel.MainViewModel”'

I'm developing with MVVM pattern. but Databinding's mainViewModel doesn't match MainViewModel. This is error and Code. plz, solve it....
activity_main.xml

<data>
        <import type="android.view.View"/>
        <variable
            name="mainViewModel"
            type="com.gram.cmr.ViewModel.MainViewModel"/>
</data>

MainActivity.kt

val binding = DataBindingUtil.setContentView<ActivityMainBinding>(this, R.layout.activity_main)
val mainViewModel = MainViewModel(this, this)
binding.mainViewModel = mainViewModel`

error message

can not access class "ViewModel.MainViewModel", Check your module classpath for missing or conflicting dependencies.

and

Type mismatch.

Required: ViewModel.MainViewModel?

Found: 'com.gram.cmr.ViewModel.MainViewModel'