Can't use Plex when internet is down even after making the recommended changes

Plex Media Server Desktops & Laptops
3

Have you seen this → [HowTo] Use Plex with No Internet which is a better document on how to do this.

I done this a few years and never have a problem if the internet goes down.

EDIT:
At the highest level, if you …

  1. have added a list of your IPs (or range) to List of IP addresses and networks that are allowed without auth …
  2. and have set Secure connections to preferred
  3. and have set your clients to not require login

… then you should be good. But these NEED to be done when you have internet. If your internet is already down then you need to wait until its back to make these changes.