Why Renfe repeatedly unavailable

Sometimes Europeans rail companies have an issue with US ISPs where they’ve detected suspicious activity and they just block everyone with Cox, or Optimum cable or whatever ISP from their website or app.

So, you could try booking the ticket on the Renfe app using your cell phone’s data instead of your WiFi.

Forget renfe book today on trainline
https://www.thetrainline.com/

Trainline sells tickets for both Renfe and it's competition

What Jazz said. Trainline is SO much easier. I could never get Renfe to work for me - got to one page where it asked me, for the 3rd time, to enter my phone number and it didn't have the US country code and you couldn't manually enter it, so....

Only God herself can tell you what is going on with Renfe’s wonky website. www.TheTrainline.com works great and is user-friendly. You can also book directly with the private train company, IRYO, which has high-speed trains running on the Madrid-Cordoba-Seville route. IRYO sells its train tix up to one year in advance of the train’s departure date. www.IRYO.eu/en

Many thanks to you all for your quick replies and referrals to sites that WORK! You are a tremendous resource to travelers like me, who get stuck!

Renfe website seems to be having problems even with its European service at present - with people being put into a queue before seeing web results. This isn't normal, so perhaps they have a tech issue.

Anyway, even at the best of times Renfe is frustrating, so I'd consider using an agent like trainline. That also has the advantage of showing non-Renfe services on the same route.