KLWP won't install

Trying to install KLWP but i get error 504 can't be installed. Tried all of the fixes google shows for the error but nothing fixed it. I use a Lenovo tab 2 A10-70F.

That error is not related to Kustom itself, thats a Play Store error i have no ways to fix it, usually those kind of problems fix themselves after a few hours, please try again now. Otherwise you can always manually install Kustom from https://kustom.rocks/klwp/apk

What to do if the google play app say "This App is not available in your country"?

I dont have control of that either, i just select "all countries" and then Play Store does the rest, you can still rely on manual download though