Hi,
My smartphone doesn't completely insert in the mobile phone holder !
Is this normal... due to the thickness of my Samsung Galaxy Note 3 Neo (8.6 mm) ?

Hello there. We apologize for the inconvenience. The Osmo Mobile 2 supports smartphones 58.6-84.8 mm wide and up to 8.4 mm thick. You can double check it here: https://www.dji.com/osmo-mobile-2/info#faq