Could not get user information / Could not authenticate since 2021-12-15

Hi! I'm aware of #294 (closed). Since 2021-12-15, 2FA or no, I'm not able to access my pixelfed.social account with mostly the error message Could not authenticate and sometimes Could not get user information, even though that was possible with another — in my opinion less suited — Pixelfed Android client (with 2FA).