I got "This is not available to you" or something like that, which I've never seen before. A few refreshes later (I also don't have a twitter) it worked though.

For me, this was caused by a buggy service worker; unregistering the service worker (from about:debugging > "This Firefox" > "Service Workers" on Firefox, dunno how on Chrome) should fix the issue

You don't need a Twitter account to enjoy a tweet.

...but I enjoy enjoying not having Twitter.