Remove Duplicate Homebrew Apache launchd Service

If brew services start httpd succeeds but brew services list shows an error with root as the user, you likely have a leftover system LaunchDaemon from a previous sudo brew services invocation alongside the user LaunchAgent. Remove the system daemon to resolve the conflict.

brew services stop httpd || true
sudo brew services stop httpd || true
sudo launchctl bootout system /Library/LaunchDaemons/homebrew.mxcl.httpd.plist 2>/dev/null || true
sudo rm -f /Library/LaunchDaemons/homebrew.mxcl.httpd.plist
brew services cleanup
brew services start httpd

After this, brew services list should show httpd as started under your user.