It is compatible. You need to jump through the email confirmation hoop before it’ll actually work with the app though. So if your account is new, that’s probably the reason.

Besides that, it could just be the mass influx of new users that are fleeing Instagram.

Because news broke that Meta lobbied for the TikTok ban. So people are now boycotting Meta platforms like Facebook and Instagram. Since Pixelfed is an Instagram clone and recently launched the app, it has gained a ton of popularity. The timing of the app launch honestly couldn’t have been better, because it gave all of the fleeing Instagram users a nice convenient place to land.