In this article, Divydeep Agarwal, CTO of Branch Messenger, shares a story about a bug that prevented certain users from logging into their accounts after the launch of a new web build. The issue was found to be related to Angular's built-in date pipe and only affected Internet Explorer (IE) users. With the help of error tracking system Sentry, the team discovered the specific compatibility issues with IE and fixed the problem in about four hours. This highlights the importance of using an error tracking system to quickly identify and fix bugs that impact user experience.