using a self-signed certificate results in a request error

I use to self signed certificate for dev. In node code I try to get some recources from the same domain on another port

import request from 'superagent';
...
const key = fs.readFileSync('certs/server.key');
const cert = fs.readFileSync('certs/server.crt');
....
       try {
            const agent = request.agent();
            const response = await agent
                .get(runtimeUrl)
                .key(key)
                .cert(cert)
                .buffer(true);

            return response.text;
        } catch (error) {
            logError(error);
        }

but get error:

Error: unable to verify the first certificate
[1]     at TLSSocket.onConnectSecure (_tls_wrap.js:1060:34)
[1]     at TLSSocket.emit (events.js:182:13)
[1]     at TLSSocket._finishInit (_tls_wrap.js:639:8) code: 'UNABLE_TO_VERIFY_LEAF_SIGNATURE', response: undefined }

[budarin]

Thanks! It helped!

[budarin]

I’m sorry - I have found solution: instead of using IP it should be used machine name! Thanks!