Tutorial from Discord, thank you @SilentWater
1. Removed dwarium and all settings.
2. Restarted my PC. Checked in %appdata% folder - I couldn't find a Dwarium folder there after uninstall. Admins have recommended to remove Dwarium folder from here if it exists after uninstallation.
3. Installed 6.4.4 given by @Altarie above.
4. Login and ran the game - worked.
5. Installed 6.9.0 from the link by @Altarie - Stable version did not work - white bar on top.
6. I Kept the client open for 1-2 mins, it auto-downloaded the Alpha build 6.9.0-alpha
7. Closed the client to install the alpha build. Now it works fine. But it's on Alpha channel (In settings)
FYI - Important in step 6 to keep the client open till you get a windows notification about the alpha install. Since with the white bar covering the top, you cannot access settings (assuming you face the same issue I did)
6.4.4
https://warofdragons.com/info/news/?show=news&id=6510
6.9.0
https://warofdragons.com/info/info/index.php?obj=cat&id=183
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Try this, as far as I know that's not work for everyone, but... still can try
Issue is reported to the programmers already.