Are you getting interviews at all? It could be your resume and not necessarily your skillset. Do you have a bachelors?
How would you feel about taking a (possibly large) pay cut? You should be a good candidate for a Jr admin position, but it would most likely pay much less. Devs, in my opinion, can make great system/network admins. Once they know the job well enough, they can generally find good ways to automate and improve business functions and processes. I wish I had gone in with programming knowledge...I see many tasks that could/should be automated, and it's tough knowing there's a better way but not knowing how to do it.
Assuming you're starting at zero, If I were you I'd do some independent learning of network and server technologies. Even if it's not on the job experience, this knowledge can help show potential employers that you have the motivation to evolve and learn new things. Having your own lab at home and being able to talk about it in an interview can only do you good.