Error 400 when I use my android app

[Oleg3]

I am the developer of android app. About 6 month ago I have migrated to API v2, and there was no problem. A few days ago I have started to recive the messages from some of my users about the error 400 when they intent to link with Dropbox. I personally intended to link Dripbox from my device, and also received the same error.

What could it be?

[Greg-DB · Accepted solution]

Did you make any changes to your app's configuration on the App Console recently, perhaps accidentally?

Specifically, please check that your have "Allow implicit grant" set to "Allow" on the app's page on the App Console, since you do need that for the app authorization flow used by the Java SDK. If it's set to "Disallow", switch it to "Allow" and try again, and let me know if that doesn't help.

[Oleg3]

Thanks, Greg! Now it works!

By the way, What does "Allow implicit grant" mean? Why did it work before with "disallow" and now did not?

[Greg-DB]

Thanks for following up. I'm glad to hear that's working now. The "implicit grant" is another name for the "token flow", which is the OAuth app authorization flow used by the Java SDK on Android. You can read more about it in the documentation if you wish.

That was always required to be set to "Allow" for this to work. Did you (or maybe anyone else who has access to your account) change it to "Disallow" recently by any chance? Let me know if not, in which case we'll look into it.

[Oleg3]

I entered in Dropbox console after I had been notified notified about error by users. So, it was not possible to change it before. And I am the only one who has access.

[Greg-DB]

Thanks! We'll check on that.