This is because Facebook limits access to your page based on geography. To manage your Facebook Geography blocking to show or hide your Page only to people in some countries, you have to:
1. Make sure that you are a Facebook admin.
2. If you're an admin; from General on the settings, click Country Restrictions
3. Add one or more countries and choose to hide or show your Page to viewers in those countries
4. Click Save Changes.
Here's the link to read more: Facebook Geo-block