What's the going app/service these days for helping users with remote access? For example if I have a call from someone in another state (or anywhere really) that needs my help to download, configure, ...

Since the error pertains to accessing a remote system, the very first step of troubleshooting would involve checking the network connectivity. Restart the computer ...

Remote access — the ability to control a computer from a different location over the network — might not be something you need to use every day. However, it does come in handy in certain situations.