- System not given any types of error message while trying to log-in.
- There is no error message in logger
- There is no problem in code
- Even though, tried to run a sample script in server but I didn't
Then tried to narrow down the error scope by checking PHP, Apache, Mysql settings and check the application storage and got that "There is no space in document root." which was the culprit for this problem. Even though application couldn't flash a single message because there was no space to show a message.
That's it. So, I think anyone should keep it in mind about storage.