Kodi 14.2 buffering issues

Hi, I am new to using Kodi, I purchased an apple set top box and want to stream movies and sport, but it has taken to constantly buffering, I am simply using the box plugged into a sony tv and it has up until recently been ok with movies. I do not use it all that often and it is linked to my house wifi with an excellent signal as we have super fast! fibre optic, download 65 – 70 mb and upload of 25 – 28mb any help appreciated, not technically adept so an easy answer would be appreciated.