Regarding your concern, the error "Invalid key hash" may occur due to the following reasons:
・ Interference from your logged in Facebook account
・ Incorrect acquisition of information from an unauthorized application.
If the account is registered before the application was available in the specific country, there are possibilities that the application were obtained via unofficial methods.
Please be advised that if the application obtained from sources besides the official Google Play Store, we will not be able to provide support.