How to resolve this proxy error

BrowserNotFoundError: Failed to start a browser:

  • Chrome: HTTPSConnectionPool(host=‘’, port=443): Max retries exceeded with url: /storage/v1/b/chromedriver/o/LATEST_RELEASE (Caused by ProxyError(‘Cannot connect to proxy.’, OSError(‘Tunnel connection failed: 400 Bad Request’)))

Hi, @adb_2022! Can you share more information?

  • What libraries and keywords are you using?
  • What Python packages and what versions (these are defined in the conda.yaml file)?

Checking firewall and network proxy requirements might help in some cases.

Library: RPA.Browser.Selenium
*** Keywords ***
Open the intranet website
Open Available Browser

conda.yaml file contents:

  • conda-forge


  • python=3.7.5

  • pip=20.1

  • pip:

    • rpaframework==14.0.0

The error message seems to indicate that Open Available Browser is trying to download chromedriver. That fails due to a proxy error. Do you perhaps use some kind of proxy on your machine/network? Or a firewall? Or anti-virus software?

Yes there is a firewall and anti-virus software as this is a company provided system.

Could you please help me with these commands as given in Firewall and network proxy requirements

set http_proxy=protocol://ip:port
set https_proxy=protocol://ip:port

Hi, the best course of action is to get our guides to your company’s IT department or go over them together.
With these outgoing proxy setups and scanners we have seen quite a bit of variance and we have built up pretty extensive tool support around these, but we cannot have general documentation around these.

Basically the set -commands above create environment variables that define the address of the proxy servers. Those addresses are defined by your IT. It would also be best if the IT side would set those variables for all users in your team/department etc. as they really are needed for a lot of tooling to work.
It is quite common that the proxy settings are only set for the browser level and this is a bit of a quirk on Windows that it is not automatically setting these environment variables. Most tooling depends on these because those variables are used in macOS and Linux.

I am about to re-write that firewall/proxy page so any feedback on the content there is appreciated.

BR, Kari