"You need to choose a number." appears when you click Buy Number without selecting one of the radio buttons under Available Numbers (that list only appears after a search returns results). If the search itself returns a red error box instead, the SMS provider (Twilio) rejected the request — usually because your account's SMS profile isn't connected yet. Opening Sprwt SMS Profile Information once creates the connection automatically; if your business is outside the US/Canada that page isn't available to you at all, so contact support instead. If an area code simply has no numbers available with both SMS and voice enabled, no error is shown at all — the Available Numbers section is just left empty, so try another area code. Purchase/card-charge errors are shown at the top of the page after you're redirected back from checkout.