Groovy Error

Connector ReleaseTask not working. Please help!!

I need to release a task after the user decline for doing in two tasks (Task preview and Task register) what converges into a Service Task with this connector.
The "if" only is a filter who decline one of those tasks
userTaskId and userTaskId is the taskAssigneeId from "ProvidedVariables" each operation each Human task from diagram.

//Connector code
import org.bonitasoft.engine.api.ProcessAPI;

ProcessAPI processApi = apiAccessor.releaseUserTask();