You are probably aware that the simplest answer to fix our recruitment problems is to do more of what's working, and immediately stop doing what is not working.
However, I wanted to give you a partial list of things you could look at doing to improve your results even more...
What can we change about how we are marketing the job?
Extra: Start a sponsored campaign with a small budget. Linkedin Jobs and Indeed sponsorship are popular options, however there are also other options to consider, like paying for an ad instead of a job on Linkedin or using Facebook and Twitter ads that point to your job posting on your site.
It is optimal if you can document the change in your process and track the process to see if the changes are working.
There are obviously more things we can do, however this can be a good start for things to consider. Feel free to ad your ideas below or reach out to me with questions.