Hi Name,
Firstly, I want to thank you for pursuing the role of (INSERT JOB ROLE) with (INSERT COMPANY NAME).
I regret to advise you that on this occasion your application has not been successful.
I thought you demonstrated strong skills in (INSERT SKILL & EXAMPLE.) However, for this role we’re looking for skills in (INSERT LACKING KNOWLEDGE OR SKILLS.)
In terms of constructive feedback, I think it would be valuable to: (INSERT LEARNING/ SKILL BUILDING/ DEVELOPMENT OPPORTUNITIES)
Good luck in your job search.
Kind regards, [NAME] [POSITION]