skywest rejection

I got an email from skywest 2 weeks ago saying they want to proceed with the interview process. asked me to sign the contract and to fill out the sterling background check info etc. I signed the contract and filled out the sterling info. after 10 days I got an email today they regret to inform me I was not chosen for the position. I was under the impression I was going to get an interview.

did my sterling background check come back bad or is this normal thing for them to reject candidates?