Because I believe the problem here is the Android system, not Obsidian.
When clicked on these buttons, Obsidian tries to open the system’s “Allow Write Permission” in the stock Files app to let you choose a folder to set as the vault. The problem then is that somehow the system doesn’t allow Obsidian to use the Files app; then error occured.
For me, even I don’t have the same problem, by disabling the stock Files app through adb I was able to repro this.
Again, I’m not sure what’s the exact case on your side, but if the case is just the Files app got disabled, then do these:
- Enable “USB Debugging” on your phone. (How?)
- Connect your phone to a computer
- Install ADB tools if you don’t have one.
(What is ADB?)
- Do
adb shell pm enable com.google.android.documentsui in the adb window.
And everything should be working again.
Edit: I missed one important step up there…