The question was:
Based on what I have read on a travel forum (Fodor’s), RENFE now has a policy that unless you have actually purchased a train ticket while physically in Spain during the last year, you will not be able to do it online — the site will reject your CC info. But, apparently there is a website, which is much easier to use than RENFE’s, where you can buy your tickets in advance, getting all the RENFE discounts, with an out-of-Spain credit card. The site is rumbo.es
Read all the good advice on this topic here.