Instance Security center not loading properly and displaying 'Page not found' error. Issue Opening /isc portal displays multiple 'Page not found' error on the home page. ReleaseALLCauseThe reason this is happening is that the OOB Header Menu is missing three angular templates: menuTemplate, item-added-tooltip.html and spDropdownTreeTemplate. It appears that these have been associated with the customer header widget. ResolutionIn order to resolve this, change the templates to use the OOB Header Menu widget, or change the Security Center header to use the custom Header Menu instead of the OOB Header Menu. To do this, follow the steps outlined below:1) Navigate to the security menu header in sp_instance_menu table (https://nashectricdev.service-now.com/nav_to.do?uri=sp_instance_menu.do?sys_id=335c900853321300a8ed21fac2dc342c)2) In the Widget field, change the value to mention the custom header menu3) Save the record