event log 50050

in RobotStudio
Hi all,
I am hoping someone is able to help me understand the meaning of event number 500500, position outside reach?
I can see that the robot is well within the reach of the position it is destined to go to, and it used to go to this position but recently is comes up with this error 50050 position outside reach on its way to the position.
I hope i have posted this in the correct forum as i am new to this.
thanks everyone,
yakov.