ST01 Trace abort after few seconds

Hello everybody,

i have a problem with the ST01 trace-function. The traces aborts after few seconds and under last change the system change the entrie back to:

############  01.01.1970 01:00:00

Kernel Release:

7.20 NUC Linux PL 426

SAP Release:

SAP_BASIS    700    0026

SAP_ABA    700    0026

SAP_AP    700    0027

SAP_APPL    600    0021