AWTFileDialog is not working in oracle forms 11g

Im using AWTFileDialog in my application, to open Windows File Dialog. This is code used to configure it

--WHEN-NEW-FORM-INSTANCE

FBean.Register_Bean('CTRL.BEAN', 1, 'oracle.forms.fd.AWTFileDialog');

FBean.Invoke('CTRL.BEAN', 1, 'setLog' ,'true');

--SELECT FILE BUTTON

:block_file.file_name := FBean.Invoke_Char('CTRL.BEAN', 1, 'saveFile' ,'Save file...,C:\,DOWNLOAD.XLSX'); 

IF :block_file.file_name IS NOT NULL THEN

  ….

ELSE

  MESSAGE('NO FILE SELECTED');

END IF;

this is not working on some users' computer. Windows File dialog is not opened, and java console log reports an error message. Users reported that issue after there was a change of company server. In other users' computers Windows File Dialog works.