sendKeys is not working for platform version Android 7.0 onwards but tap is working fine

Issues/Bugs
1

Following code is working for Android 6.0 but not for 7.0 version onwards.

AppiumDriver mobDriver;

public BookingIdentificationPage(){}

public BookingIdentificationPage(AppiumDriver<AndroidElement> driver)
{
    PageFactory.initElements(new AppiumFieldDecorator(Base.driver), this);
    mobDriver = Base.driver;
}

@AndroidFindBy(id=“et_first_name”)
public AndroidElement txtFirstName;

public void enterFirstName(String fn){
txtFirstName.sendKeys(fn);
mobDriver.hideKeyboard();
}