Are the following sentences grammatically correct?
1. This is once again to inform all the candidates who have applied for the post of the principal in this college to report for the interview on the scheduled date and time, as notified earlier, failing which they will forego their right for consideration.
2. All the candidates who have applied for the post of the principal in this college are hereby once again informed to report for the interview on the scheduled date and time, as notified earlier. Failure to do so will lead to the forfeiture of their claim for consideration.
No, neither is grammatically correct. First, each misuses the verb "inform." You can't inform people to do something. You can advise people to do something. And you can inform people that they should do something.
Second, "as notified earlier" doesn't work. You could say "as they were notified earlier" or "as mentioned earlier" instead. We notify people of information. It is people, not information, that is notified in an act of notification.
Third, you should change "the principal in this college" to the principal of this college." In your country, do colleges have principals? Here, only elementary schools and high schools do. Colleges have deans, presidents, and chancellors.
Fourth, I strongly prefer "Failure to do so" to "failing which."
Fifth, Gustavo has pointed out to me in e-mail something with which I agree: "the post of the principal of this college" would be much better if the second "the" were deleted: "the post of principal of this college."
Sixth, Gustavo has also observed in e-mail that "the forfeiture of this claim" would be better without "the": "will lead to forfeiture of their claim."
Lastly, while it is a delight to have you back, Ahmad, please remember that GE is not a proofreading site. Each thread should be devoted to a particular grammatical topic; it is not a place to test-drive random sentences for grammaticality.