@FearlessTiara18,
See this topic here for what you have discovered. It’s a global issue right now but all add-ons (that are current with this release) should still work:
https://forums.flightsimulator.com/t/addons-in-community-appear-as-not-installed-in-content-manager-after-updating-to-1-15-7-0-and-world-update-iv-although-they-are-installed/390491/83