I tried to buy a Leviathan (new temporary offer), but it doesn't work.
I tried in the application, in Firefox and in Chrome - same result.
On the other way, I was able to buy fireships.
I will report it to our Support Agents, but they are unlikely to see it before the end of the discount (on account of it being evening of the day before Christmas), so try also to raise a ticket for "Feedback on Special Offers/Discounts".
I just heard back from the Support. The issue should be resolved now (and you didn't miss the discount because it doesn't apply to special units like Icebreakers and Leviathans).
