How do I save certificate files? #31

So, I need to use nginx as my SSL handler. To do so, I need to save the certificates as files, however, when saving them like this:

await writeFile(`./LetsEncrypt/Certs/${domainDoc.domain.split("https://")[1]}/privkey.pem`, leres.privkey);
await writeFile(`./LetsEncrypt/Certs/${domainDoc.domain.split("https://")[1]}/cert.pem`, `${leres.cert}\r\n${leres.chain}`);

and running them through nginx using the following

listen 443 ssl; 
ssl_certificate ${__dirname}/../../../LetsEncrypt/Certs/${domainDoc.domain.split("https://")[1]}/cert.pem;
ssl_certificate_key ${__dirname}/../../../LetsEncrypt/Certs/${domainDoc.domain.split("https://")[1]}/privkey.pem;

my browser sees the certificate files, accepts that they are proper certificates but claims that I am using an unknown CA which isn't valid. Anyone have any idea on how to fix this?