Issues of caches in Retrofit in Android

I’ve a question. When I click the button, encrypted’s value changes, but for posting isn’t changed in the RequestBody. Retrofit always saves previous values of encrypted. Is it depend on Retrofit? If yes, how can I clear caches? I used .cache(null), but it doesn’t help. Thanks in advance.

class RemoteDataSource @Inject constructor() {
    companion object {
       var string: String?=null

        fun setEncr(string: String){
            this.string=string
        }

        fun getEncr():String{
            return this.string!!
        }
   }

   private fun getRetrofitClient( context: Context? = null): OkHttpClient {
    val authenticator:Authenticator?=null

    val encryp= getEncr()
    val  body = "{rn"Data":"${encryp}"rn}"
            .toRequestBody("application/json; charset=utf-8".toMediaTypeOrNull())

    return OkHttpClient.Builder()
        .cache(null)
        .addInterceptor { chain ->
            chain.proceed(chain.request().newBuilder().also {
                it.addHeader("Accept", "application/json")
                it.method("POST", body)
            }.build())
        }.also { client ->
            authenticator?.let { client.authenticator(it) }
            if (BuildConfig.DEBUG) {
                val logging = HttpLoggingInterceptor()
                logging.setLevel(HttpLoggingInterceptor.Level.BODY)
                client.addInterceptor(logging)
            }
        }.build()
 }

}
in MainActivity

binding.buttonLogin.setOnClickListener {
    val clientId = binding.edittxtClientId.text.toString().trim()
    encrypted = encrypt(clientId, publicKey)
    setStr(encrypted)
    viewModel.loginResponse.observe(this, Observer {

                when (it) {
                    is Resource.Success -> {
                    .....
    }
}