My app does not run on android Lollipop

Question

At a certain point in my app, payment occurs with pagseguro, and for this I open a page in a webview, responsible for this service (passing the card data by GET). When the page finishes being processed, the title of it changes with the status of the operation, and so I can pick up to work on android (yes, it is a gambiarra). The problem is that in my client’s mobile does not run, android 5.1.1 . The payment is processing until crash in the application. I installed the API 22, related to android 5.1, I created the emulator in android studio and it worked fine. With API 23 it also works on emulator and on my phone.

Could someone help me?

Follows the webview module

private void iniciaPagamentoCartao(String url, final Agenda agenda) { //1==cartao, 2==boleto
    webView.setWebViewClient(new WebViewClient() {

        public boolean shouldOverrideUrlLoading(WebView view, String url) {
            view.loadUrl(url);
            return true;
        }

        public void onLoadResource (WebView view, String url) {
            if (progressDialogPagamentoCartao == null) {
                progressDialogPagamentoCartao = ProgressDialog.show(act_principal.this,"Processando pagamento","Aguarde...",false,false);
            }
        }
        public void onPageFinished(final WebView view, String url) {


            public void onFinish() {
                String tituloPagina = webView.getTitle().toString();
                switch(tituloPagina)
                {
                    case "Erro contate o administrador":
                        progressDialogPagamentoCartao.dismiss();
                        progressDialogPagamentoCartao = null;

                        Toast.makeText(act_principal.this, "Erro interno. Contate o administrador!", Toast.LENGTH_LONG).show();
                        break;

                    case "Erro no cartao de credito":
                        progressDialogPagamentoCartao.dismiss();
                        progressDialogPagamentoCartao = null;

                        Toast.makeText(act_principal.this, "Erro no cartão de crédito!", Toast.LENGTH_LONG).show();
                        break;

                    default:
                        //faz as outras rotinas necessárias
                        String codigoTransacao[] = tituloPagina.split("~");
                        confirmaPagamento(1, agenda, codigoTransacao[1]);

                        progressDialogPagamentoCartao.dismiss();
                        progressDialogPagamentoCartao = null;
                        break;
                }
            }

        }
    });

    webView.getSettings().setJavaScriptEnabled(true);
    webView.loadUrl(url);
}