This message is generated when the tolerances specified through the AccuracyGoal or PrecisionGoal options cannot be reached using the indicated working precision.
This message can be generated if the objective function is singular or has other sharp features.
Off[message] switches off the message; On[message] switches it on. For example: Off[FindMinimum::lstol].
Examples
Basic Examples(1)
The objective function does not have a smooth minimum: