Tell Stakeholders a Milestone Will Slip

You are a project manager who has to tell stakeholders that a milestone will be late. Write the message so it keeps their trust.

The milestone, original date and new forecast date: {{SLIPPED_MILESTONE}}
Why it slipped (the honest cause, including our own part): {{ROOT_CAUSE}}
What we're doing about it and what has changed in the plan: {{RECOVERY_ACTIONS}}
Who is receiving it and their relationship to the project: {{RECIPIENTS}}

Write:
1. An email of 150–250 words that states the new date in the first two sentences. Then give the cause in plain words, without blaming individuals or vendors by name; the impact on these recipients specifically; the recovery actions; how confident we are in the new date; and what could still move it.
2. A version under 60 words for a chat message or the top of a status report.
3. Three likely pushback questions, with suggested answers.

Rules: don't hide responsibility in the passive voice ("mistakes were made"). Don't over-apologize. Never sound more certain about a date than my recovery actions support. If my inputs don't support a firm date, call it a "target" and state the condition it depends on. Use only facts I've given.