Office 365: Alert Policies vs Activity alerts

[Mihir Yelamanchili]

Environment: Office 365

We are having E1 license. I am able to create alert policies in Security & Compliance center. But when condition was met, no alerts were triggering. 

But if I do the same policy in Activity alerts section, it is triggering the alert. 

Question:

1. To trigger alert policy, do we need to have a another license?
2. Or any settings i need to activate or setup?

[#2]

Depends on the condition/trigger. There's a detailed list here: https://docs.microsoft.com/en-us/office365/securitycompliance/alert-policies

You can also refer to the recent discussion we had here on the MTC: https://techcommunity.microsoft.com/t5/Office-365/Set-activity-alerts-using-PowerShell-issues/td-p/2...

[#3]

My question is why alert is triggering in activity alert why it is not with alert policies. Office plan is the issue here?