DDJ SX Issue

I am having a bit of a weird issue with my DDJ SX. When I open up the hardware and then open up my Serato DJ, I have no control of the actual hardware and my channel 4 button 2 is blinking continuously. The software seems to work fine because the two turntables appear and I can play the music internally but not with the actual hardware. I then have to close up my Serato DJ and my DDJ and reopen them and then it works fine. What causes this to occur? Thank you for your time!