I love this idea, but it’s not working very well for me either. The first time I clicked “auth” it sent me to the correct page; however, when I clicked the button to allow it to access my account info, it went to https://nornagon.github.io/inat-bingo/ and displayed a blank page. When I refreshed the page, it switched to https://nornagon.github.io/inat-bingo/#854. Now when I click “auth” it goes straight to the blank page and behaves exactly the same way. I can change the place setting, at least.
Edit: I just tried again and it sent me to 429 Too Many Requests.