Hi paul70078, After you change the password, there should be a notification that the session has expired and it will prompt you to login again. On a mobile device, if you do not see this, remove the account and connect it again.

Thank you, and please post back with your results, it could help other users.

That wasn't the problem. I couldn't log in because it simple failed. When I entered a wrong password it said wrong password.

After flashing an other Android ROM it works, but I leave this open because the real problem isn't solved yet.

HI paul70078, I talked to a sync engineer and that message really is shown in the case of unknown error: the relevant string in a adb logcat capture is "fxaccount_sign_in_unknown_error" and is shown when there's an exception.

For further troubleshooting, if you can share a logcat of when you produce this issue, it would be helpful to further investigate.

<note to self create bug with response>

The instructions on how to capture a log like this on an Android device is pretty simple, but it does requires the Android SDK>

1. Install http://developer.android.com/sdk/index.html
2. Attach phone to usb
3. From terminal adb devices to see if the device is listed
4. adb logcat > test.txt
5. Produce the issue
6. Copy the text to a shared url or we also use http://pastebin.mozilla.org/

Action would be to add this to a bug in bugzilla.mozilla.com with all the details how to reproduce and any logs with that or other errors.

Thank you and I look forward to working more with you to investigate and create action on!