A file in the plugins folder is not a plugin
Applies to Paper, Vanilla.
What it looks like in your log
org.bukkit.plugin.InvalidDescriptionException: Invalid plugin.yml
What causes it
A jar in the plugins folder has no plugin.yml, so it is not a Bukkit plugin. It is usually a mod put in the wrong folder, or a corrupted download.
How to fix it
Remove the file, or re-download the actual Spigot/Paper build of the plugin. Mods go in /mods on Forge or Fabric servers, not /plugins.
Not sure this is your problem? Paste your log and Roastd will tell you which of these it actually matched, and what else it found.
Check your own log