Database error: automatically cleared

this afternoon ,when I login loraserver again ,it hit error and found the database is cleared ,all table is empty.
this is the second time I meet this problem ,about 3 months ago ,this happen ,and now it happen again
Is this a bug or others

version
commit 887bb2f6bb5015c18e519a3de3e422ad056fe9f4
Author: Orne Brocaar info@brocaar.com
Date: Sat Dec 16 11:04:22 2017 +0100

Vendor github.com/robertkrimen/otto.

There is no functionality in LoRa Server which clears your whole database. I should look into how your database is setup. Make sure you’re using a persistent storage. E.g. in case of Docker containers, use volumes to make sure that your state does not get lost when restarting containers. Also make sure you don’t use the same database for testing as production.

I install the loraserver follow the guide https://docs.loraserver.io/overview/ and not other setup on database
I didn’t know if the database default set will cause this problem .