HTTPS not working with authentication

Steps to reproduce the problem:

1. mitmproxy --nonanonymous

2. Set a proxy username and password in System Preferences -> Network -> Wifi -> Advanced -> Proxies for both HTTP and HTTPS.

3. Save changes. A dialog appears: Choose Always Apply

4. Open browser and navigate to a HTTPS page eg. https://www.google.ie/. This appears:

5. Fill in username and password to match those entered earlier.

6. Get the following error (ERR_SPDY_PROTOCOL_ERROR):

Any other comments? What have you tried so far?

After googling the error, I tried flushing the socket pools at chrome://net-internals/#sockets. I immediately got the same error after trying to access a HTTPS site again.

Previously I had been getting two dialog boxes; one requesting credentials for localhost:8080 and then another requesting credentials for google.ie:443 (or whatever site) directly after the localhost one.

Not sure if it matters, but the proxy credentials in my keychain:

System information

Mitmproxy version: 2.0.0 (1.0.1dev0129-0x919385d) Python version: 3.6.0 Platform: Darwin-15.6.0-x86_64-i386-64bit SSL version: OpenSSL 1.0.2k 26 Jan 2017 Mac version: 10.11.6 (‘’, ‘’, ‘’) x86_64

[Kriechi]

AFAIK: I think this settings just means “use this proxy for HTTP requests” and “use the other proxy for HTTPS requests”. So, no, macOS uses the same terminology as Chrome for something different.

[laurmurclar]

Worth mentioning that Safari on my iPhone 6 also gives me a million dialogs, as well as Safari on the Mac mentioned above