I have spent some time investigating the problem, so now I share the results.
The first step that caused the disaster was clicking "Update software".
The newest software V2.800.0000000.43.R, Build Date: 2023-08-29 (DH_IPC-HX3XXX-Leo_MultiLang_PN_Stream3_V2.800.0000000.43.R.230829) was installed...