Job searching and frustrated

So, I’m currently job searching. I’m looking to find similar employment to what I’ve been doing the past 4 years. I worked at a hospital as a Nursing Tech (a CNA without certification) I’ve applied at the 3 other hospitals within my area, but I never even get called for an interview. You can check the status of your application on their websites where you apply and my application never even gets past the first round and I’m not understanding why...On top of 4 years at the hospital, I also have around a years worth of direct support care experience (working with individuals with disabilities) and I have plenty of customer service experience. What could I be doing wrong that my applications are being overlooked like this?! I’m getting discouraged!