For those of you who have tried to sync your android accounts that have different emails and keep getting the "no value for success" error here is how I fixed mine.
1. Fully close both MW accounts on both devices
2. On the device you want both accounts on open Google Play
3. Tap top left corner (If both email address are there this may not work).
4. Tap your email
5. Click "Add Email"
6. Add your second email linked to your account your trying to sync
7. After you add it, fully close Google Play
8. Reopen Google Play and now tap on your new email.
9. Open Modern War and try to switch accounts.
10. Come back here and let us know if it worked for you also.
Cant promise this will work for everyone, but it worked for me. Hope this helps and please don't criticize me if this does not work for you, just trying to help out.
