We recently had the issue that it was not possible to access a Git repository using Visual Studio 2017 behind a corporate proxy. After having verified that the repository was accessible using a public network (without proxy) and that all the needed ports in the firewall are open, we were searching for a solution of the issue.
Finally the solution was to just add the proxy configuration in the .gitconfig file that resides in the user’s „homepath“ (environment variable HOME=“$HOMEDRIVE$HOMEPATH“):
[http] sslVerify = false proxy = http://proxy.your.domain.com:proxyport [https] proxy = https://proxy.your.domain.com:proxyport
After a restart of Visual Studio 2017 everything worked as expected without any problems!