The machine is stuck. Check for a "bird's nest" of thread in the bobbin area or a jammed rotary hook.
To effectively diagnose and repair problems with your Siruba L818FM1, it's essential to familiarize yourself with the machine's error list. The error list for the L818FM1 model includes a range of codes that indicate specific issues, such as: siruba+l818fm1+error+list+2021
Without access to specific data from 2021, I recommend checking: The machine is stuck