Currently, Dialogflow CX doesn’t have the History feature similar with Dialogflow ES. However, you can still view the ‘no-match’ user inputs from your Dialogflow CX agent.
In order to check the ‘no-match’ user inputs, you can view or export conversation logs from Dialogflow CX using Stackdriver by following the steps below:
1. For Dialogflow CX Logging, go to the agent Settings in the upper right corner of the Dialogflow console and enable the "Enable stackdriver logging" option. Note that logs generated after enabling this option will be recorded in Stackdriver (Operations Logging).
2. Once some logs are collected, go to Google Cloud Platform Console’s Logging section.
3. In the Log’s Explorer section, you may expand the Query results entry to view the ‘no-match’ user inputs.
4. In the Log’s Explorer section, click on the Actions dropdown and select Create Sink.
5. Enter Sink Name, select Sink Service and Sink Destination.
6. When prompted to Choose Logs to include in the sink, you can use inclusion filters like the following to extract logs by project_id, agent_id, session_id, etc.
resource.labels.project_id=”sample-project-id"
labels.agent_id="sample-agent-id"
labels.session_id="sample-session-id"
For more information about exporting logs, kindly check this Exporting Logs with the Google Cloud Console documentation. You can also try exporting Stackdriver logs using the Cloud Logging API, kindly check this documentation for more details.