Description

You can face an issue like this on Events page in KWTS:

Sometimes the search on the Events page works correctly. Sometimes not.. If you collect har-file (HOW TO) from Events page with reproduced issue you will see an error also in it:

Also you can find an error in diagnostic_info\logs\var\log\kaspersky\kwts\extra\webapi.log:

Then you should check Maximum event log size (https://support.kaspersky.com/KWTS/6.1/en-US/174773.htm) in settings here: diagnostic_info\klinfo\worker_settings.xml

Maximum event log size set to 10 GB. 

How to solve a problem

You should set it to 9 GB. The KWTS architecture is not designed for a large event database size.