ErrorPluginsSIG-PL-011

Exception in a plugin's event handler (Could not pass event)

What it looks like in the log

Any one of these lines is enough. The agent matches them locally, on your server.

logs/latest.log

A plugin feature that reacts to player actions (clicks, joining, chat) does not trigger
In the log: “Could not pass event <Event> to <plugin> vX” and a stack trace

A plugin's event handler (listener) threw an exception. Paper keeps running, but the plugin's action for that event was not carried out.

A plugin bug (NullPointerException and the like in its classes)
The plugin accesses a disabled plugin or an unavailable resource
Incompatibility with the server version, or a conflict with another plugin that modifies the same event

Use the evidence to identify the event (the name after Could not pass event) and the plugin (after to); the exception is on the next line and in Caused by:.
If the trace points to a disabled plugin or the database, deal with that cause first (errors earlier in the log).
Update the plugin; in case of a conflict, temporarily disable the plugins listening to the same event one at a time to find the culprit.
Report it to the plugin author with the full trace and versions if the error reproduces on the latest version.

Translated from the Russian original; log lines are quoted verbatim.