Simple Log Service provides the Logtail diagnostics feature to help you troubleshoot the exceptions that may occur when Logtail collects logs. This topic describes how to use the Logtail diagnostics feature.
Prerequisites
Logs are collected by using Logtail. For more information, see Data collection overview.
Important log collection is enabled for the project to which the required Logtail configuration belongs. For more information, see Enable the service log feature.
Background information
The Logtail diagnostics feature is available in advanced and basic editions.
Advanced edition (recommended): provides an exception diagnostics dashboard that displays the exception information of Logtail. You can query information about exceptions that occurred long time ago.
ImportantIn the advanced edition, the dashboard relies on the important logs in the specified project. For more information, see Log types.
Basic edition: provides information about exceptions in the previous 1 hour.
Procedure
Log on to the Simple Log Service console.
In the Projects section, click the project that you want to manage.
On the tab, move the pointer over the Logstore that you want to manage, click the
icon, and then choose Advanced Diagnostics or Basic Diagnostics. 
View diagnostic information.
ImportantTo use the advanced edition, make sure that important log collection is enabled. For more information, see Important logs.
Basic Diagnostics
The Log Collection Error panel displays all Logtail collection errors for the Logstore. You can click an error code to view the details of the error. For more information, see How do I troubleshoot the common errors that may occur when Simple Log Service collects logs?
Advanced Diagnostics
On the Logtail Exception Monitoring page, you can view exception information including Active Logtail and All Alarm. For more information about the Logtail Exception Monitoring dashboard, see View data reports. For more information about error codes, see How do I troubleshoot the common errors that may occur when Simple Log Service collects logs?