I cant purchase the limited sale offer from the start screen.

@GabbahYT

There are a few possible reasons why this pops up

Did you use the payment method before, if not you Bank might blocking the process.

There might be an error with your Browser, deleting Cookies and clearing Cache or using an different Browser might help.

You could have made an small misstep and then tried too often and now the system is blocking you for an period of Time, normally 24h hours.

So if after 24h wait Time the error persists you could call BW and see if they can sort that out with you.