A couple of questions.
Did you buy the box version and are attempting to update it?
If so then try to download the whole game from impusle instead. Also make sure that it successfully activated on your impusle account.
Have you downloaded other games succesfully with Impusle?
If No
Could be a firewall issue or a bad install of Impusle, might even be a permission problem with windows (run as administrator or check your security settings).
If yes
It could be that Impulse is just getting swamped with request in your area and is having a hard time verifying or it could be that you're game's ID isn't in their database yet and will be added in later(if boxed).
I would try again tonight and if it doesn't work I would contact stardock support in the support forums for elemental
https://forums.elementalgame.com/forum/877
There might also be a post there where others have solved the problem.
You could also check out the impusle forum
https://forums.stardock.com/forum/457