Delivery times: what do I do if an order is late?

Following what I wrote last week (on delivery times drugged by Amazon Prime), I have a question for all manufacturers or suppliers specialized in outsourced processing (mechanical or otherwise):

what do you do when (if it happens, but I am sure it does occasionally) you are late in making a delivery?

I ask this because another imposing criticality of recent times is linked precisely to such a scenario: a precise delivery deadline is established with the customer and then, for one reason or another, this date cannot be respected.

Because, let’s be honest, all enterprises (all, without exception), can encounter unexpected events that cause delays.

A delay in the delivery of raw materials. A technical malfunction on a machine. An independent supplier involved in the realization of the part suffers a delay further down the chain. Or anything else that comes to mind.
But listen: I am not talking about regular delivery delays which – often quite wrongly – foreign customers associate to Italian enterprises. I am talking about situations that can not be predicted.

So: what do we do when the inevitable happens?

Is it better to warn the customer as soon as possible? Or not, hoping that the delay can, in some way or another, be recuperated?

I ask this because, in our experience, in both cases we end up in situations that are difficult to manage.

Let me explain. If the delay is notified too close to the delivery date, the customer reproaches the supplier for not warning him in time, so as to allow him to reorganize his work accordingly (perhaps rescheduling the production of that specific article which requires the delayed parts).
A rightful approach, there’s no doubt about it. I wouldn’t say otherwise.

If it weren’t for the fact that, in the event that the delay is notified well in advance (obviously when it is possible to predict it and this is not always the case), it could end up triggering a customer/supplier dynamic perhaps even more difficult to manage, mainly because the customer “finds it hard” (to put it mildly) to accept the delay and starts a series of fairly useless meetings with the aim of avoiding the delay, ending up wasting hours, if not entire days of work.

And then, for instance, when we do manage to recuperate and make the delivery on the initially established date, another set of problems arise. Because the referent was notified of the delay and, in the meantime, has rescheduled his work plan.

However you look at it, in such cases it is very difficult to find the right approach when dealing with customers. Nearly impossible, I would say.

So, I’ll ask you again:

in your opinion, what could be the best approach in these circumstances?