When a cartesian constraint goal is sent to STOMP via MoveIt, the target_frame is equal to world (see this line) and thus fails because the world frame is not part of the robot state. This behavior occurs with the panda_moveit_config from moveit_resources package because it uses a floating virtual joint. When a virtual joint is not a fixed frame, the model frame becomes the parent of the virtual joint.

If I change this line with this below it works normally:

//target_frame = model->getModelFrame();
target_frame = model->getRootLinkName();