RFD900 won't connect and solid red

Hi I have some problem for connecting RFD900+ to Mission Planner. So at first my RFD was in green blinking but then I suddenly know nothing the RFD turn to solid red. What do I have to do to make it back normal? I’ve tried to relflash using RFDtools bu I don’t know how to do it. Please someone if there’s any problems like this or solution that would be great to solve it. Thx