Hi Dika,
Could you double click at the node ""/sap/public/bc/icf/logoff" in SCIF. Then select Tab "Error Pages" > Tab "Logout Page".
Select Redirect to URL option. Enter the SAP Fiori Launchpad url in Redirect fields. Save and try again
If you system is lower than SAP_BASIS 730 SP-lvl2. check note 1509851
Regards,
Piyawat