Paper and Spigot plugin.yml errors
"name ... contains invalid characters"
Server log
org.bukkit.plugin.InvalidDescriptionException: name 'My!Plugin' contains invalid characters.
What it means
The plugin name may only contain letters A to Z, digits, _, . and -. Anything else, including letters with accents or symbols such as !, & or @, makes the server refuse the plugin.
What causes it
The name in plugin.yml has a character outside that set.
How to fix it
Before
name: My!Plugin
After
name: MyPlugin
The pretty name players see can go in description or prefix instead.
Check the whole file. Paste your plugin.yml or drop the plugin jar into Permistry. It finds this and about 40 other problems, and explains each one in plain words. It runs in your browser and nothing is uploaded.
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