You can no longer create accounts with Yahoo domains other than "@yahoo.com",

As of Jan 1, 2021 many countries now require KS creators to show Shipping AND VAT/Fees/Taxes on Kickstarter Rewards - not just 1 price for "shipping". So we will do that in our Pledge Manager, after the campaign. Yea, we know...this sucks and is against everything Kickstarter used to be about (the world now views KS as a store, not as a creative platform sending rewards to backers for helping bring the vision to life)

you mean Action Form, right?

Similarly to a cell phone setup, you prepay your email quota. Although they famously used to offer credits that ‘never expired’, new changes mean that credits now expire after 12 months (or, if purchased before May 15th 2019, they’ll expire on May 15th 2020).