RubyInstaller: Why MSYS2 Updates Can Fail Behind a Proxy
RubyInstaller's development toolchain uses MSYS2 package tooling. A working RubyGems proxy is not evidence that pacman has the same route.
Ruby starts correctly, but the development-toolchain setup fails during an MSYS2 update. You have reached another package system, not another attempt by RubyGems to fetch the same gem.
RubyInstaller uses MSYS2 for the relevant development tools. Its ridk workflow can therefore reach a stage where MSYS2's package tooling, including pacman, performs the network request.
Identify that stage in the log. Check the proxy environment and supported downloader behavior from the MSYS2 process, not merely the proxy configured for gem in a different Windows terminal.
A persistent Windows environment change also does not rewrite the environment of every process already running. Launch context can explain why a newly opened toolchain shell behaves differently from an installer that was started earlier.
Use the current RubyInstaller and MSYS2 instructions for the installed versions. An old workaround that deletes package databases and then refreshes everything combines several changes; it does not establish that deleting the database repaired a proxy connection.
Keep the network route, repository metadata, and package-signing errors distinct. Configure the approved proxy and required trust for the actual request before altering package state. Once the toolchain update works, a later RubyGems failure is a separate client to diagnose.