I did quite a search for this both online and offline, but couldn't find a satisfiable answer. Some of my colleagues suggested terminologies like Dashboard, Home page, Welcome page, landing page, etc. It's true that a great deal of web apps redirect users to a dashboard page after login but the page is called dashboard, not because of this but because it has stuff like app status or profile status. Also a home page is the usual term for the first page in an application which can be available even when not authenticated. Welcome page is also a term usually used for an entry point page just like home page. And from numerous searches regarding Landing page, I guess it's a term coined by marketers and advertisers synonymous to lead capture page.
A landing page, sometimes known as a "lead capture page" or a "lander", or a "destination page", is a single web page that appears in response to clicking on a search engine optimized search result or an online advertisement. - https://en.wikipedia.org/wiki/Landing_page
So, for the above reasons, i don't think any of the above terms are good enough for the description "The page to which the user is redirected to, after successful login".
I expect my fellow stack exchangers will find an answer for this or share their views regarding this question. Thanks in advance :)