Fastly Malicious hits

Security
1

we have a particular UA and would hit us 300M times in 3 days Actually from Amazon Datacenter.

The user agent is :Microsoft Office/16.0 (Windows NT 10.0; Microsoft Outlook 16.0.4849; Pro) As why would outlook come from AWS what might be the possible reason of hit

2

Can you explain how this relates to Fastly? Are you saying that you have a Fastly service (Delivery or Compute) which is receiving this unwanted traffic?