APM not showing data in Kibana

I'm using APM Real User Monitoring JavaScript Agent Reference [4.x] with my React application.
When I try to send error to APM Server with apm.captureError(new Error('...')); the POST request is correctly sended to the APM server and I receive a 202 response, but I don't see that error in Kibana.

Can you check the APM Server logs for any hints on what's going wrong, and also check that the server can reach Elasticsearch?