Move the robot in a direcction until contact

When in the program add the instrucction direct until contact, in the program appear the fault C271A1, in the inside the instrucción add a accion the sync() for to try improve it, but the problem persist.
Thanks for the information.

This problem is solved, the program had a instruction Thread, when in this part the program add a sync(), all correct, but the alarm only appear in the moment that program add the instruction direct until contact, otherwise the program function very well