[mitmproxy] Can not verify mitmproxy certificate

Dear all,
I am Khanh . Currently, I would like to set up mitmproxy to decrypt HTTPS traffic.
My scenario is:
Windows7 -> Ubuntu(Gateway)(install proxy)
On Windows 7, I have this configuration:
Gate way:

And this is the ifconfig of ubuntu machine

And we set up the gateway like this:

After installing mitmproxy 0.9.2
I can capture HTTP traffic from Windows machine

But in windows machine, I can not access to mitm.it server to get the certificate
The error: traffic is not passing through mitmproxy

When I installed certificate manually(getting from ubuntu machine and install it on windows machine), the certificate seems not trusted.

Please help me for this situation
Thank you

Have you added mitmproxy certificate in “Trusted Root Certification Authority”? You can do this with Windows’ certmgr.msc utility.