Programm crashes unexpected and often

I'm trying the program but it doesn't work properly. It crashes often ... sometimes after 5 minutes sometimes after during typing a query :'-(

Useful extra information

DB4S v3.12.1 [built for x86_64-little_endian-lp64] on Linux Mint 21.1 (linux/5.15.0-153-generic) [x86_64]
using SQLite Version 3.33.0
and Qt 5.15.1