Kibana EVP_DecryptFinal Error - OpenSSL Version?

I'm trying to set up Kibana's server SSL and keep encountering an error related to decrypting the certificate. I created my certs through openssl, and Googling indicates an openssl mismatch might be causing this error. I know my Linux machine has openssl 1.1.1, is Kibana trying to decrypt the cert using a different program?

The error (viewed through journalctl) is

FATAL  Error: error:06065064:digital envelope routines:EVP_DecryptFinal_ex:bad decrypt

Relevant kibana.yml code is:

server.ssl.enabled: true
server.ssl.certificate: /etc/kibana/mycert.crt
server.ssl.key: /etc/kibana/my-cert.key

It turned out I was giving kibana the encrypted key, when it really wants the decrypted key. Changing this fixed the problem