When you use Logtail to collect logs, errors may occur. For example, regular expressions may fail to be parsed, invalid file paths may exist, and traffic may exceed the processing capabilities of shards. Simple Log Service provides the Logtail diagnostics feature to help you troubleshoot errors that occur when Logtail collects logs.
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?
After you fix existing errors, check whether errors exist. Historical errors are displayed before they expire. You can ignore the errors and check only the errors that are reported after you fix the historical errors. Logtail reports errors at 10-minute intervals.
NoteTo view the complete logs that are discarded due to parsing failures, log on to your Logtail server or Logtail container and check Logtail operational logs. Log path:
Host:
/usr/local/ilogtail/ilogtail.LOGContainer:
/usr/local/ilogtail/ilogtail.LOG