Deleted code (APK problem)

1.I just made a huge part of my app. I’ve got some issues with thunkable App. It didn’t showed everything I’ve got on computer. So I went back to the home page of thunkable. And half of my code (over 1000+ blocks) were lost. Why it didn’t saved? Is there any button to save my app. 2.And when i downloaded my app (on Android )to see what’s wrong. After trying to install it showed me " an error in installing package". Can anyone help me?

Edit: I even created app with button and label and it still shows “an error while installing package”

I am not sure about the lost blocks. Maybe someone else has an idea there. Can you provide any additional information on the error your getting while installing the apk file? Is it possibly a security issue? If so, maybe this link will help.

Option: “Unknown sources” was turned on earlier. And it still don’t work.

Here is a photo of error.

Can anyone help me? It still doesnt work

I made a new account and i tried to install app and it worked. So can anyone help me with old (this) account. All apps even ALOHA doesn’t want to install. This from my old account doesn’t have an Thunkable logo. But from new account has one.

I found same your problem.
some project that have more components can not install.
but some example project can install.

I found differrent about 2 file
The file that create completed but not have thunkable logo cannot install to Android.
test-Navigator.apk can install to device
but 3s.apk cannot install