There is no specific log out page. The SAP UI5 application needs to execute navigation to the standard log out ICF node /sap/public/bc/icf/logoff with a redirect URL. For this ICF node, you can define an external alias (with the same name /sap/public/bc/icf/logoff) with a log out redirect (error pages → Logoff Page → Redirect to URL). This action will affect the entire server.
For more information on fixing issues with the log out redirect method just described, see 1509851 . Applying an HTTP white list is also recommended, which you can apply by using 853878 .