Exception after adding this plugin to Grails 3.2.4 app

[anti43]

Caused by: org.springframework.core.serializer.support.SerializationFailedException: Failed to serialize object using DefaultSerializer; nested exception is java.lang.IllegalArgumentException: DefaultSerializer requires a Serializable payload but received an object of type [grails.plugin.springsecurity.LoginController]

grailsVersion=3.2.4

URI
/login/auth
Class
java.lang.IllegalArgumentException
Message
Cannot serialize; nested exception is org.springframework.core.serializer.support.SerializationFailedException: Failed to serialize object using DefaultSerializer; nested exception is java.lang.IllegalArgumentException: DefaultSerializer requires a Serializable payload but received an object of type [grails.plugin.springsecurity.LoginController]
Caused by
DefaultSerializer requires a Serializable payload but received an object of type [grails.plugin.springsecurity.LoginController]