Data lost and screen like first installation

This morning all ok
In the afternoon opening app I have only the wellcome screen and no accounts, no data.
Is like I’m installed the app for the first time.
Yes, I have no a backup, but why happened this.
No new installation of other apps or anything strange or different.
Where are data ? Where are settings ?
All is strange.

Some more information would be good. Especially vendor, make and Android version. What was the last thing you did on your device. Any updates installed. Etc.

E.g., if you have a Google Pixel 8, there is a known bug with the memory controller. Your data is gone. You should send in the device for a repair or exchange immediately.

E.g., if you have a Samsung Galaxy S23 US spec and have activated the secure storage, there is a known bug. Your data is still there, but you need to send in the device for a warranty repair. Samsung will restore your data for you.

Etc. pp.

Hy, tks for replay.
619 / 5.000

this morning (I live in Italy) I read my inbox regularly, after about an hour I watched a film on Prime. At 4pm I launched the app and the configuration screen appeared as if it were the first time I had used it. From the app info there was no longer any data or even cache, I can not understand. Nobody used my smartphone. All other apps are working properly and without any damage. Luckily from my PC I can always access my emails via GMAIL and also with Thunderbird. I made a mistake in not backing up the settings, but losing the data for no reason it’s very strange.