Below are the points I confirmed:
+ With the same username & password, I was able to login in the past
+ With the same username & password, I am able to login via Chrome’s Incognito browser

Above 2 points confirmed that, issue is caused by Cookies.
Clearing Cookies need a Browser restart, which is a difficult task specially when its a busy day at the office & you have lot many tabs opened which you don’t want to close. So what is the alternative?

First of all, let’s try to understand “What are Cookies?
An HTTP cookie (web cookie, browser cookie) is mainly used to manage user sessions, store user preferences, and track user behavior.
It is a small piece of data that a server sends to the user’s web browser. The browser may store it and send it back with the next request to the same server. Typically, it’s used to tell if two requests came from the same browser — keeping a user logged-in, for example.

Any website we visit, is composed of thousands of files. When we visit the site for the first time, as the browser can display the files stored in its cache much faster than it can pull fresh files from a server, the browser will save pieces of the site locally. The next time we visit that site, the cached files will help cut down the page load time. These cached files are cookies.
Now, at times, we would bookmark the login page of a Website. Usually, this is not a problem, but when websites update, remembering that old version can sometimes cause a problem, clearing cookies and cache tells the browser to start over fresh.

How to clear Cookies for a specific site without restarting the Browser?

  • Browse the Website that you want to login
  • Press F12 key to open Chrome Developer Tools
  • Click on ‘Application’ Tab within the Dev Tool
  • On the Left Pane within the Tool, expand ‘Cookies‘ within ‘Storage‘ category
  • Highlight the Website & on the Right pane, you would see ‘Clear All‘ button ahead of ‘Filter‘ search box
  • Try to login using the same credentials now & you should be able to login now.