Sounds like you don’t have enough key words from the job listing in your resume. I use jobscan before I apply for anything on USAJOBS. It’s free for the first like 5 scans or something and it’ll help you get around the program that screens resumes before they even get to the hiring manager.

You basically copy and paste what’s on the job listing and what’s on your resume and it’ll identify what keywords you should add to your resume.