unable to get local issuer certificate

[oldthreefeng]

Environment

• OS: centos 7
• Erlang/OTP:
• EMQ: v4.1.0

DOCKER IAMGE: emqx/emqx:v4.1.0

use mount path add tls cert

        - mountPath: /opt/emqx/etc/certs/key.pem
          name: emqx-ssl-key
          subPath: tls.key
        - mountPath: /opt/emqx/etc/certs/cert.pem
          name: emqx-ssl-cert
          subPath: tls.crt

Description

A description of the issue

openssl s_client -showcerts -servername mqtt.gaoding.com -connect mqtt.gaoding.com:443
CONNECTED(00000003)
depth=0 CN = *.gaoding.com
verify error:num=20:unable to get local issuer certificate
verify return:1
depth=0 CN = *.gaoding.com
verify error:num=21:unable to verify the first certificate
verify return:1
depth=0 CN = *.gaoding.com
verify return:1
.....

i dont know how to resolve this. but may related to tuna/issues#1342

i have tried :

RUN apk update && apk add --no-cache openssl-dev gnutls-dev ca-certificates 

nothing changed... any solutions for me?