Profit ess treadmill showing error 4 and won't start?

Hi I have a pro fitness folding treadmill- series number hy452580-d1, which is showing er 4 in the time counter on the consol. It has been working, on the day I assembled it, but when I went to use it again- nothing! I have spoken to pro fitness team who told me to check the connections under the cover near the motor etc which I did, I have also disassembled everything and re attached the wire connections incase anything is loose. Still nothing! I have only had this 1 week and so frustrated, please help!