This message may appear when you solve a model with uncertainty and chance constraints using robust optimization, and you’ve checked the box “Auto Adjust Chance” in the Solver Model dialog Stochastic tab, or you’ve previously viewed the Solver Results dialog and selected the “Auto Adjust Chance Constraints” option.  It means that the Solver has found the best ‘improved solution’ it can; the normal constraints are satisfied, and the chance constraints are satisfied to the Chance level that you specified in the Solver Parameters dialog.

This is usually a very good solution, but it does not rule out the possibility that you may be able to find an even better solution by manually adjusting Chance measures based on your knowledge of the problem, and re-solving.