title: Google Sign-In suddenly not working
body: <p>I am working on an Android app that uses Google Sign-In.</p>
  
  <p>Everything was working fine until recently. I stopped working on this project for about two weeks and got back to it yesterday, and the Google Sign-In is suddenly not working anymore. When I click sign in, the Sign-In popup opens, I choose my account and... nothing happens.</p>
  
  <p>So as I did not change anything in the code related to the Sign-In, I started to search everywhere else.</p>
  
  <p>First I noticed that my <code>compile 'com.google.android.gms:play-services-auth:11.4.2'</code> could be updated to 11.6.0, so this is what I did.</p>
  
  <p>I ran the app again and it was now asking me to update Google Play Services, so I clicked on update button but again, nothing happened. I tried multiple times but it didn't change anything. So I started looking somewhere else.</p>
  
  <p>I went to the <a href="https://github.com/googlesamples/google-services/blob/master/android/signin/app/src/main/java/com/google/samples/quickstart/signin/SignInActivity.java" rel="nofollow noreferrer">link</a> where I found the code sample for Google Sign-In to see if anything has changed and... yea it has changed, 10 days ago the sample was updated so I updated my code and now, nothing better, just that the Sign-In popup does not appear now when I click sign in.</p>
  
  <p>So I started looking more deeply at the logs, and here are the problematic lines :
  <code>W/GooglePlayServicesUtil: Google Play services out of date.  Requires 11717000 but found 11577470
  W/FA: Service connection failed: ConnectionResult{statusCode=SERVICE_VERSION_UPDATE_REQUIRED, resolution=null, message=null}
  W/LoginActivity: signInResult:failed code=12500</code></p>
  
  <p>So apparently, it should be related to Google Play Services... Note that I don't get the "Update Google Play Services" popup anymore.
  Most of the answers that I found regarding this kind of issue suggested to try on another emulator with a lower API, or downgrading Google Play Services compile line, so I tried both.
  I used to run my tests on a Pixel XL with API 27, I tried on a Nexus 6P with API 25, on this one I can get to the Sign-In popup but when selecting my account I get 
  <code>W/LoginActivity: signInResult:failed code=10.</code>
  I also tried on two real devices that are OnePlus 3 with API 25 and Samsung Galaxy S6 Edge with API 24, I get the same error on these two than on Nexus 6P. Moreover I don't find anything regarding the meaning of the error code 10.
  Regarding Google Play Services downgrade, some classes of the new code sample are not recognized if I do so. Also, it seems not to be a Google Play Services issue anymore when trying on devices with lower API than 27.</p>
  
  <p>UPDATE : I found that the error code 10 means "The application is misconfigured". I don't see how since nothing has changed between the time everything worked find and the time it stopped working, anyway I generated a new debug.keystore, a new configuration file and added it to my /app. And obviously it still does not work.</p>
  
  <p>UPDATE 2 : As I tried everything thinkable, and I knew something was wrong with my debug.keystore (I read everywhere that this file should regenerate itself if deleted when building a project, which was not the case for me). I uninstalled/reinstalled Android Studio, hoping that it will at least solve this problem. Well I had tons of files that I don't remember in .android folder and now I have only 1 folder and 2 files, obviously debug.keystore is not one of them. So this made me remember that there is another way of getting the SHA1 signature and this is what I explain in my answer post. But still there is something wrong with my debug.keystore so if anyone has an idea...</p>