You have written your logline in the blandest possible way. While it does tell us the protagonist and what’s standing in his way, it doesn’t grab us. (You are tying to ‘sell’ your story with your logline, not just describe it)

1) ‘Indiscretion’ — is the worst possible word you can use, It’s a word politicians use to downplay and affair.

2) ‘receives an e-mail’ —we really don’t need to know that delivery method, only that he is being blackmailed.

3)’ Nathan Carson’ — don’t need his name but do need to know a little about him, is he a family man, a politician, what will he lose if the affair is discovered.

Here’s an attempt, it needs tweaking because I don’t know the details of your story:—

—“After being caught in an extramarital affair, a greedy business tycoon finds himself blackmailed by an opportunistic hotel concierge, only to his horror it isn’t money he must pay.”

Not perfect of course, we still don’t know what he will lose if the affair is discovered. It should be something personal or life altering, (Maybe his wife owns 51 percent of the company and he will lose control if she divorces him)

Good luck with this, the idea looks intriguing.