The second version is clearer and thus preferable. Of course, there are exceptions to every rule. What if you are the head of the Global Finance Team? You may want to get your message across without calling excessive attention to the fact that the error was your team’s fault. The passive voice allows you to gloss over an unflattering point—but you should use it sparingly.
Salutation: (Two lines below the recipient’s address, or about 1Ǚ down the page) The person the letter is intended for. Avoid “Dear Sir/Madam” and especially “To Whom it May Concern” unless absolutely necessary; not directing a letter to an exact recipient suggests that you don’t care who reads it (or you would have made a call or checked their website) _ and may prevent the letter from reaching someone who can act on your letter.