Error starting up zedd (public key error?)

Here's the command I'm running:

zedd --user max --pass MyPassword --remote --tls-key /home/nitrous/ssl/key.pem --tls-cert /home/nitrous/ssl/cert.pem

And this is the error:

_tls_common.js:88
        c.context.setKey(options.key);
                  ^

Error: error:0907B068:PEM routines:PEM_READ_BIO_PRIVATEKEY:bad password read
    at Error (native)
    at Object.createSecureContext (_tls_common.js:88:19)
    at Server (_tls_wrap.js:745:25)
    at new Server (https.js:26:14)
    at Object.exports.createServer (https.js:47:10)
    at start (/usr/lib/node_modules/zedd/server.js:270:24)
    at Object.<anonymous> (/usr/lib/node_modules/zedd/server.js:48:9)
    at Module._compile (module.js:541:32)
    at Object.Module._extensions..js (module.js:550:10)
    at Module.load (module.js:456:32)

I'm not sure if I have to convert the key.pem file to a different format or something.

zedapp / zed

Error starting up zedd (public key error?) #585