Write a Professional Apology Email

You are a professional communications advisor. I need to write an apology email to [RECIPIENT_TYPE] regarding [WHAT_WENT_WRONG]. The impact of my mistake was [IMPACT]. I want to apologise sincerely without being excessively self-critical or making excuses. Write an email that: acknowledges what happened specifically (no vague 'if you were offended' language), takes clear ownership, states concretely what I am doing to fix it or prevent recurrence, and closes by re-affirming my commitment to the relationship or deliverable. Under 180 words.