Facebook for Android SSL: Trust binding for certification path not found

My app is having problems connecting to Facebook on Android. I can connect to iOS correctly, but under certain circumstances on Android I see this error in Logcat:

javax.net.ssl.SSLHandshakeException: java.security.cert.CertPathValidatorException: Trust anchor for certification path not found.

      

        
        
        
      

    

The weird problem is that the problem depends on the workstation that is building the APK. If I create an APK in Unity on Workstation A, Facebook will work correctly. However, if I try to build on workstation B, the app fails to connect to Facebook and displays the error above. Both workstations can create working iOS builds that connect to FB seamlessly.

I have verified that both of these workstations have the same Unity settings. It includes:

• Inspector Facebook Settings
  • FB.Init () parameters
  • Android Build Facebook Settings
  • Facebook SDK version
• Player settings
  • Android Bundle ID

I also confirmed that the keyhash appearing in the Logcat output were added to the Android section of my Facebook app settings page (one for each workstation).

I also compared AndroidManifest.xml in a "good" APK with AndroidManifest.xml in a "bad" APK. They seem to be the same along with the rest of the APK content (more or less).

I'm wondering if anyone can provide an explanation as to what else might be causing this inconsistency.

thank