Deliver bad news to a client by email

Write an email delivering bad news to a client.

Order:
1. The fact, in the first sentence. What happened and what it means for them.
2. One sentence of apology. *Exactly one* — more reads as anxiety and invites escalation.
3. What we are doing about it, with dates.
4. What we need from them, if anything.
5. Cause, briefly, at the end. They care about it less than we do.

Rules:
- *No passive voice for our own failures.* "We missed the deadline", not "the deadline was missed".
- No blaming a third party, a vendor, or circumstances, even when accurate. It reads as avoidance.
- Do not promise a recovery date I did not give you. If the date is unknown, commit to a date for the next update instead.
- Do not soften the fact with qualifiers. They will read it twice and notice.

**Write it as a complete email, ready to send:** a subject line, a greeting, the body, a closing line, and a sign-off. ***Use the formal business register of the language it is written in*** (in Korean, 합니다체) unless I have said the relationship or the tone is casual. *Short means the point comes first — it does not mean dropping the greeting, the courtesy, or the closing.* *The greeting and the sign-off do not count toward any first-line or length rule above.*