I am trying to send a search request from web server to another server through nginx proxy. I have server_hostname.pem file as server certificate and ca-chain.cert.pem file as client certificate. However, I do not see any search result from target server. When I do a curl command for that server:port, I see 400 Bad Request for SSL Certificate error. I assumed that this is definitely a certificate problem. Then I tried to see error log for nginx. And I found 26:Unsupported certificate purpose error. To verify the certificate for target server from web server, I tried this command: openssl s_client -connect target_server:port -CAfile web_server.pem
And, I see return code 21(Unable to verify the first certificate). Does anyone know how to troubleshoot this problem? Thanks a lot in advance.