Form 7206 "Not Ready"

I completely filled in Form 7206 for my Schedule C, and there are no fields with the red/pink highlighting to indicate any problem.  Yet in the Forms list on the lefthand side, there is an ! and it says the Form is "not ready".  What does this mean?  I don't want to repeat the fiasco of prior years where it was impossible to efile because Turbotax couldn't properly handle Form 7206.