Apology for Delay to a Client

Subject: Apology for Delay in Service  

Dear [Client's Name],

I wanted to personally apologize for the delay in [specific service or delivery]. We encountered an unexpected issue with [brief explanation of the issue], which has caused a temporary setback.

We are working diligently to resolve this and ensure it does not happen again. We expect to have everything back on track by [new estimated date].

Thank you for your understanding and patience. Please let me know if there's anything more we can do to assist you during this time.

Best regards,

[Your Name]
[Your Position]

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