Certificate verification error, unable to get local issuer certificate

I’ve installed python 3.6.5 on my Win7, then use command: pip install mitmproxy to install the latest one and the version is 4.0.4, all is success. Then install the cert for IE.

When I start to visit web site: https://www.winit.com.cn, it reports:
502 Bad Gateway
Certificate verification error for xxxx: unable to get local issuer certificate(errno:20, depth:0)

However, if I visit other https websites all OK! Any help will be great! Thanks!

PYTHON can’t verify a trusted site with imcomplete certificate chain
em,known,wont fix…

You can try --ssl-insecure parameter.

That’s works for me, thank you so much!