I have a red flag

So I’ve had problems with getting a job for yrs and I’ve recently run into a few friends that are in management with a dollar general kinda place and a McDonalds kinda place ( not those places ) anyways they’ve both tried to get me a job and they both said I had a red flag and i wasn’t aloud to be hired . They said security deals with that department and they didn’t know but wtf is that the reason I’ve had suck a huge issue getting work ?! How does I fix it ?! Not really expecting answers just needed to get my frustration out .