整合不和谐的PHP错误（Xenforo）

Question

当我启用Xenforo插件时，会显示此信息。我的服务器在SAME php版本的另一台主机上可以做到这一点没有错误。所以这不是插件问题。

An exception occurred: Undefined index: instant_invite in 
/home/blackfor/public_html/library/EWRdiscord/Listener/NavTabs.php on line 17  
XenForo_Application::handlePhpError() in EWRdiscord/Listener/NavTabs.php at line 17
EWRdiscord_Listener_NavTabs::listen() call_user_func_array() in XenForo/CodeEvent.php at line 90
XenForo_CodeEvent::fire() in XenForo/Dependencies/Public.php at line 495
XenForo_Dependencies_Public->_getNavigationContainerParams() in 
XenForo/Dependencies/Public.php at line 371
XenForo_Dependencies_Public->getEffectiveContainerParams() in 
XenForo/FrontController.php at line 637
XenForo_FrontController->renderView() in XenForo/FrontController.php at line 158
XenForo_FrontController->run() in /home/blackfor/public_html/index.php at line 13

截图

我目前正在为Xenforo使用[8WAYRUN] Discord Integration插件。