# Certificate verification error, unable to get local issuer certificate

**URL:** <https://discourse.mitmproxy.org/t/certificate-verification-error-unable-to-get-local-issuer-certificate/1171>\
**Category:** help\
**Created:** [August 13, 2018, 10:48am UTC](https://discourse.mitmproxy.org/t/certificate-verification-error-unable-to-get-local-issuer-certificate/1171 "2018-08-13T10:48:12Z")\
**Posts on this page:** 4\
**Page:** 1

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**Author:** ![peterwangcn](https://avatars.discourse-cdn.com/v4/letter/p/b2d939/32.png) [@peterwangcn](https://discourse.mitmproxy.org/u/peterwangcn)\
**Post date:** [August 13, 2018, 10:48am UTC](https://discourse.mitmproxy.org/t/certificate-verification-error-unable-to-get-local-issuer-certificate/1171/1 "2018-08-13T10:48:12Z")

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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](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!

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**Author:** ![liushengqi000](https://yyz2.discourse-cdn.com/flex030/user_avatar/discourse.mitmproxy.org/liushengqi000/32/341_2.png) [@liushengqi000](https://discourse.mitmproxy.org/u/liushengqi000)\
**Post date:** [September 8, 2018, 4:10pm UTC](https://discourse.mitmproxy.org/t/certificate-verification-error-unable-to-get-local-issuer-certificate/1171/2 "2018-09-08T16:10:37Z")

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PYTHON can’t verify a trusted site with imcomplete certificate chain  
[https://bugs.python.org/issue27970](https://bugs.python.org/issue27970)  
em,known,wont fix…

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**Author:** ![Gigiarum](https://yyz2.discourse-cdn.com/flex030/user_avatar/discourse.mitmproxy.org/gigiarum/32/278_2.png) [@Gigiarum](https://discourse.mitmproxy.org/u/Gigiarum)\
**Post date:** [September 10, 2018, 8:28am UTC](https://discourse.mitmproxy.org/t/certificate-verification-error-unable-to-get-local-issuer-certificate/1171/3 "2018-09-10T08:28:59Z")

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You can try `--ssl-insecure` parameter.

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**Author:** ![peterwangcn](https://avatars.discourse-cdn.com/v4/letter/p/b2d939/32.png) [@peterwangcn](https://discourse.mitmproxy.org/u/peterwangcn)\
**Post date:** [September 25, 2018, 3:48am UTC](https://discourse.mitmproxy.org/t/certificate-verification-error-unable-to-get-local-issuer-certificate/1171/4 "2018-09-25T03:48:08Z")

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