Since the official Open GApps project has largely moved on to newer Android versions, direct links for 6.0.1 can be buried.
Even with the correct version, things can go wrong. Here is the fix for the top 3 issues on .
GApps (Google Apps) is a packaged bundle of Google proprietary applications and services that are not included in AOSP (Android Open Source Project) builds. For Android 6.0.1 (Marshmallow), GApps packages provide the Google Play ecosystem and related components needed for a complete Google experience on custom ROMs or AOSP-based devices.