In order to use the Alexa devices like Echo, Fire TV and Fire Tablet, you need to have an Amazon account. If you are in Malaysia, most probably the country setting for your devices will follow the country you have selected for your Amazon account. If it is Malaysia, then you may face problem installing certain apps like YouTube and Netflix in your Fire TV or Fire tablets because certain apps are restricted to certain countries and Malaysia is not one of those countries. To overcome this, you have to change the device's country setting in your Amazon account and here is how you do it:
First, login to your Amazon account and go to Your Account page.
Next, click on Manage content and devices.
Then go to Preferences tab.
You will find Country/Region Settings on this page. Click on the Change button.
Change the country to United States and fill in the rest with a fake address. Once it's done, click on the Update button.
That's it. You should be able to install those restricted apps after you reboot your device.