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当退出登录清理缓存时出现下面的文字 请问是什么情况

您当前的访问请求当中含有非法字符，已经被系统拒绝
PHP Debug

[Line: 0026]member.php(discuz_application->init)
[Line: 0071]source/class/discuz/discuz_application.php(discuz_application->_init_misc)
[Line: 0552]source/class/discuz/discuz_application.php(discuz_application->_xss_check)
[Line: 0355]source/class/discuz/discuz_application.php(system_error)
[Line: 0017]source/function/function_core.php(discuz_error::system_error)
[Line: 0024]source/class/discuz/discuz_error.php(discuz_error::debug_backtrace)