Error findElementById

[QuynhLy]

helpp me!!!
I findElementById with Login and Register are oke.
But, when i test another function ( Book hospital) by steps:

1. login successful
2. FindElementById in function BookHospital
   it’s error: An element could not be located on the page using the given search parameters.

Here my error:
driver.findElementById(“group3f.vn.vpet.quynhly:id/navigation_home”).click();