Unresolved m999 error

Alright, so I have the Robo R1+ and when I try to start a print everything's heating up like it should. after the auto leveling the error comes up (m999) and it just stops in the back right corner, saying it isn't heating to the correct temp but when I check to see what the temp is, it's still at what I set it too. It tells me that I can resume the print but it wont move from the corner and the time is still moving. Does anyone have any ideas on what's going on, and how I'd go about fixing it?