What I think:
The configurator was a dud. They got jumped by the high load on the server(s), and may be, the configurator was in fact "not ready for rollout".
So they have likely stopped the service and are fixing problems or installing a more capable hardware or both.
In one of my yersterdays readings there is written "when [in May] the configurator is ready ... ". Sounds very much like a second try. In the meantime they point us to the specs to pick the options manually. That's why I and others always end up somewhere different than the configurator - there is simply none ready which has all options.
I am even not able to load my stored configuration. And this is a strong indicator to me, that things don't work es planned.
However, I would say that a configuration on an international platform with different models per country and different options per model and different configuration packages automatically excluding redundant items and giving automatic advice for better prices with other combinations is really not a trivial matter. I've also seen bad things at Mercedes. Rest assured there is some overtime being worked there at the moment - and maybe a few heads will roll.