Atom Editor: Configure proxy settings
At the Windows platform you have to take care that you do not edit the .apmrc file located in the %USERPROFILE%\.atom\.app\.apmrc. The file which is resides in %USERPROFILE%\.atom\.apmrc is the right one.
The file %USERPROFILE%\.atom\.apmrc is always being overwritten when atom starts.
Add the following lines to %USERPROFILE%\.atom\.apmrc and replace localhost:5865 with your proxy settings.
http-proxy = "http://localhost:5865"
https-proxy = "http://localhost:5865"
proxy = "http://localhost:5865"
And check settings