Unable to add HTTPS subscription

[Squiggle]

I have been trying to subscribe to Hoyhablamos podcasts using MusicBee without success.
The feed (if I go to the site, right click and examine properties) is at:- https://www.hoyhablamos.com/feed,  although the site creator has advised that it is https://hoyhablamos.com/podcast.

Neither works for me in Music Bee (and nor does https://www.hoyhablamos.com/feed/podcast). If I go to 'subscriptions' and ‘add subscription link’ followed by any of the above URL’s, the info button says ‘unable to verify the validity of this URL – Invalid URL. The format of the URL could not be determined’. Changing the https to http does not work either.

If I go to ‘subscriptions’ and use the ‘Search Podcast directory’ button and search under Education and then type in 'Hoyhablamos', it does show up as available in the iTunes directory - but the 'subscribe ' button is greyed out (the website indicates that downloads are available for both iTunes and Android but there is no RSS button). I have been advised that it may be because the feed is https rather than http, but there could be some other cause. Can anyone suggest a fix or explanation for this?

Website is Hoyhablamos.com and I am running Windows 10 (64 bit) Home edition.
I have similar issues with the website Vein ndos – the search facility in MusicBee recognises it in the iTunes directory, but again the ‘subscribe’ button is greyed out. It too is https rather than http.

[Steven]

are you using the latest version from the downloads page: 3.1.6590 or above

[Squiggle]

Thank you! I had thought that I was on the latest version but found that I was on 3.0.6132. Updating MB has solved the problem with HoyHablamos.
 
I have also tried subscribing to Vein ndos (which now appears in the MB iTunes directory with a 'live' subscription button). However, only one episode is downloaded when I subscribe (and the others do not register at all). I suspect that this is something to do with their website, but any ideas as to how to subscribe to the other ep[isodes would be welcome.

Regards & thanks again