S4810 rebooted itself

Hello,

Can someone help me to check why S4810 switch rebooted itself? Before rebooting I fond the logs:

critical local7 %STKUNIT0-M:CP %CHMGR-2-STACKUNIT_DOWN: Major alarm: Stack unit 0 down - IPC timeout
critical local7 %STKUNIT0-M:CP %IPC-2-STATUS: target stack unit 0 not responding
error local7 %STKUNIT0-M:CP %IFMGR-3-IFA_COMM_FAIL: Failed to contact IFA in slot: 0

Thank you!