Unable to see Alerting in UI

Hi, I have a Percona Monitoring And Management app running, which comes with a Grafana front end. The Grafana version is 5.4. Currently, I cannot see the Alerting (bell) button on the side panel of the UI. I have already modified my grafana.ini file and set Alerting enabled to true, as per the documentation. Is there other config that i missed?
Thanks and hope some one can help.