W3C validator says 'feed does not validate' 'url must be a full URL'… whats wrong with it?

Question

Validating my feed, it has an enclosure with a URL of

https://archive.org/download/NigelFarageAPersonalMessageToNorthernIrelandVoters./Nigel%20Farage,%20a%20personal%20m

Answer 1

And if you don't have httpS then your SSL says your page isn't secure. #feedvalidator step up. There are a ton of feedback/complaints about this on the support forum here https://groups.google.com/forum/#!forum/feedvalidator-users

More specifically here: https://github.com/rubys/feedvalidator/issues/16