Ionic4 fingerprint sensor issue

I have added fingerprint plugin given in official doc, but it is not working in my android mobile (i tested 3 to 4 mobile). getting the following issue.can anyone help me to solve the issue.

ERROR Error: "Uncaught (in promise): TypeError: Object(…) is not a function.

Did you include the plugin in your app.module.ts file? Are you waiting for the platform to be ready before calling it?

yes, sir. still, I am getting this error.