Cannot reauthenticate to kbin.earth with newest version of Interstellar

[evanfoster]

Describe the bug

After upgrading the app, I am unable to refresh my login on kbin.earth. I'm able to log in using the web interface.

Steps to Reproduce

1. Open app
2. Click "Refresh login"
3. Enter username, password, 2FA code
4. Click "Allow" on the permissions prompt

This also fails when attempting to remove and add the same account using the "Switch accounts" dialog

Version

v0.11.2

What client platform(s) are you seeing the problem on?

Android

What server platform(s) are you seeing the problem on?

Mbin

Additional context

[I] TIME: 2026-02-10T11:50:17.481184 Switch accounts @kbin.earth -> Badabinski@kbin.earth
[E] TIME: 2026-02-10T11:50:18.026079 OAuth authorization error (invalid_grant): The refresh token is invalid..
[E] TIME: 2026-02-10T11:50:19.988303 OAuth authorization error (invalid_grant): The refresh token is invalid..
[E] TIME: 2026-02-10T11:50:19.988922 OAuth authorization error (invalid_grant): The refresh token is invalid..
[E] TIME: 2026-02-10T11:50:34.053870 PlatformException(CANCELED, User canceled authentication, null, null)

I couldn't seem to find a way to stop the log from being truncated, unfortunately.

Also attached are some screenshots:

[evanfoster]

Here's a redacted version of the URL being opened:

https://kbin.earth/authorize?response_type=code&client_id=REDACTED&redirect_uri=interstellar%3A%2F%2Fauth&code_challenge=REDACTED&code_challenge_method=S256&scope=read+write+delete+subscribe+block+vote+report+user+moderate+bookmark_list

I don't know if it matters, but I'm using URLCheck which intercepts URL open requests. I haven't seen it break flows like this before, but it bears mentioning.

[jwr1]

Interesting, I just tried updating the app on my Android, and I was able to log back in just fine with my kbin.earth account.

If you haven't already, can you try removing all kbin.earth accounts (including guest) from your app, and then try logging back in after that? You may have to temporarily add a different server's guest account and select it to do so.

[evanfoster]

No joy, unfortunately! I added a lemmy.world guest account, deleted my account as well as my kbin.earth guest account, then re-added my kbin.earth account but received the same error after clicking "allow":

[jwr1]

Well, I honestly have no idea. It seems like the redirect URL is not reaching Interstellar for some reason, as that would be the reason to see the "User canceled authentication" error. @olorin99, do you have any ideas at all? Maybe it's an issue with the flutter_web_auth_2 package.

Just to be sure, could you try clearing your app data and then trying it one more time? You can export your database in case you have any important settings you want to save (Settings -> About -> Debug -> Export database).

[jwr1]

What Android device and OS version do you have?

[evanfoster]

The problem was URLCheck. It's not passing data back to the application for some reason. This all worked with URLCheck in the previous version of Interstellar, but I'm hesitant to say it's due to Interstellar. Something may have changed with URLCheck that I'm not aware of. Everything worked as expected once I changed my default browser back to Chrome.

It probably doesn't matter any longer, but I'm on a Google Pixel Pro 9 running Android 16.

[jwr1]

We did actually change the way we handle OAuth authorization in this most recent update. We switched from using an in-app web view to using a Chrome Auth Tab (for Android specifically, at least).

[jwr1]

I'm guessing URLCheck would need to specifically support Auth Tabs in order for it to work.

This issue might be related: TrianguloY/URLCheck#527

[olorin99]

Hmm I just installed URLCheck to test and didn't have any problems with default URLCheck settings and Fennec as the browser.

screen-recording.mp4

[SilkyPants]

I have been experiencing this issue as well, and to @evanfoster point - once I changed my default browser on my Android phone to Chrome it worked perfectly.

Before when it was set to Firefox I would be stuck in a loop of either the authorise blank page, or when I cleared my storage to start again I was locked in a loop granting access for the app.

[jwr1]

I'll try installing a different browser on my phone and see if I can reproduce the issue. It's possible we might just need to go back on this change (for Android at least).

[SilkyPants]

I'll try with Fennec, and maybe some other browsers on my device later tonight. It could just be something with Firefox specifically?

[olorin99]

Did some testing with different browsers and URLCheck. All on a Pixel 9a with Graphene OS

Default Browser	Result	Note
Vanadium	Success
Chrome	Success
Fennec	Success	Needed to manually close the browser window
Firefox	Success	Needed to manually close the browser window
URLCheck -> Vanadium	Fail
URLCheck -> Chrome	Fail
URLCheck -> Fennec	Success	Needed to manually close the browser window
URLCheck -> Firefox	Success	Needed to manually close the browser window

Vanadium is based on Chromium and Fennec is basically just Firefox with the proprietary bits removed so it can be on fdroid. So it looks like the redirect gets lost in the URLCheck -> Chromium route but works ok otherwise.

[jwr1]

It seems like we might need to go back to using a webview then? Obviously, the auth tab solution is hit-or-miss depending on how your Android device is set up.