If you're getting an error like:
error sending request for url (http://ryeland.pouncelight.games/v1/events): connection error
Then two things are likely:
If you live in a country that restricts internet access, then that is probably the root cause. Our daily themes are hosted from a server in Germany. Some countries (e.g. Russia and China) block network traffic to European servers. If that applies to you, and if you normally use a VPN / tunnel to access services in Europe, you might want to use it while playing Tiny Glade -- or at least enable it temporarily to download the daily theme.
There's of course a chance that our theme server might be experiencing an outage. You could check with https://onlineornot.com/website-down-checker to see whether it's just you or not. Enter http://ryeland.pouncelight.games/v1/events into the form, and hit "Check". If the tool confirms that our server is down, please let us know in the Steam forums. Note that other "website down detectors" might incorrectly claim the server is down if they only check the root URL. The server doesn't respond to ICMP ping.