http://www.daytondailynews.com/news/...wd8oMxlnavOyJ/
"The Ohio Board of Education in 2016 permanently denied Robert L. Miller Jr. the required three-year pupil activity permit required to coach. The denial, which is at the state board’s discretion, was based on a 1999 court-martial conviction at Wright-Patterson Air Force Base for attempted larceny, conspiracy to commit larceny and other related charges. A permanent denial makes an individual “ineligible to apply for any license issued by the state board of education.”
So basically it sounds like he stole something in 1999 and the OBE wouldn't give him the required permit that would allow him to coach.