A child custody order is meant to be followed. As much as it is in your power to do so, you should make sure that the order is followed. Of course, this isn't always possible. Things like illnesses and unexpected events do happen.
If you or your ex is purposefully not following the child custody order, you could be interfering with custody or visitation. This is a very serious matter that must be treated accordingly. In fact, it can sometimes lead to new custody orders or even more serious legal action.
There are many ways that interference can occur. One of these is that one parent might refuse to bring the child to the other parent in accordance with the order. When this happens, the parent who is missing time with the child might decide to turn to the court for help.
Child custody interference might also occur if one parent doesn't let the other parent make the decisions that the parent is supposed to make for the child. For example, if one parent makes faith-based decisions for the child and says the child should only go to a specific faith's church, the other parent should respect that decision. Of course, this can be more complicated if the parents are supposed to share the decision-making responsibilities.
If interference is an issue, you should remember that interference doesn't have anything to do with child support. This means that you can't withhold support if you can't see your child. It also means that the other parent can't keep your child from you.
Source: FindLaw, "Custody or Visitation Interference," accessed July 27, 2017