This topic lists the various troubleshooting procedures for ENS. ENS2 Resubscription and Badge Count Accuracy LimitationsThe ENS2 uses the Exchange Web Services (EWS) subscription to notify the Boxer application of any changes in an end-users mailbox, including the email notifications. The Boxer application initiates these subscriptions with the ENS and the ENS subscribes a user's account with the EWS. Troubleshooting Accessibility Issues to the ENS ServerThis topic describes the steps to troubleshoot the accessibility issues to the ENS server on a cloud ENS installation and on an on-premises ENS installation. Troubleshooting the Console Configuration IssuesYou can configure the ENS2 settings using the configuration key and configuration value provided by the Workspace ONE UEM console. Troubleshooting ENS2 Notification IssuesENS notifications are applicable only for emails in the Inbox folder. The notifications do not work for Calendar events, sub folders, and so on. This topic describes the steps to troubleshoot the ENS2 notification issues for emails in the Inbox folder. Troubleshooting Connection Issues to the ENS DatabaseWhen installing ENS, use the SQL authentication and not the Windows authentication to access the ENS database. This topic is applicable for ENS on-premise installation only. Troubleshooting SSL ErrorsUse the SSL pinning certificate tool when the notifications are not delivered to the devices. This tool is only used for troubleshooting purpose and is not a mandatory step during installation. The following error message appears in the ENS logs while posting the notifications to CNS: The underlying connection was closed: Could not establish trust relationship for the SSL/TLS secure channel. ENS2 Response Code and Error Code DetailsIf the Boxer application sends a request to the ENS, the ENS processes the request and sends a response with a response code and message to the Boxer application.