Windows default browser is IE edge, if you don't change to chrome, you will be blocked by IE edge due to security, no certificate.
Specially when you finish install arcgis portal, finish install arcgis server, finish install arcgis data store, it popup a URL open a page in IE, you have to continue finish up the post install configuration in browser.
If your browser is IE, then you can't do because IE blocked this page.
You have to copy the URL in IE, paste in Chrome to see the content. In chrome, you still need to click 'advanced' , then click 'Proceed' with risk.
See this sample, to open portal page in Chrome and IE result in different situation.
How to change windows default browser
