我知道 rethinkdb 指南使用自签名证书作为示例。如果我想使用我购买的真实证书，如何将捆绑包添加到服务器 conf？我将购买的证书和密钥添加到配置中：
driver-tls-key=/etc/ssl/star.cert.key
driver-tls-cert=/etc/ssl/star.cert.crt
Openssl s_client 给了我以下内容
Verify return code: 21 (unable to verify the first certificate)
以此作为证书链：
depth=0 OU = Domain Control Validated, OU = PositiveSSL Wildcard, CN = *.s0nr.co
verify error:num=20:unable to get local issuer certificate
verify return:1
depth=0 OU = Domain Control Validated, OU = PositiveSSL Wildcard, CN = *.s0nr.co
verify error:num=21:unable to verify the first certificate
verify return:1
---
Certificate chain
0 s:/OU=Domain Control Validated/OU=PositiveSSL Wildcard/CN=*.s0nr.co
i:/C=GB/ST=Greater Manchester/L=Salford/O=COMODO CA Limited/CN=COMODO RSA Domain Validation Secure Server CA
我怎样才能正确使用这个证书？