Typical Message:
Abnormally large email volume detected for exampledomain.com at 08/26/2021 18:00 Eastern Daylight Time. XX messages came through in that hour vs the YY hourly average.
Explanation:
This alert indicates that there's been a large surge of inbound Email (good or bad) hitting your tenant on Proofpoint Essentials. Usually we trigger this warning when it's around 5x your average volume (and the average is a rolling average).
Usually it's nothing really concerning but you may want to have a quick look at the message log in proofpoint essentials for anything unusual about the massive amounts of emails received.
1. Most of the time it's a just a newsletter that comes in where most the users are subscribed to it.
2. It could be a spam or phishing wave that may have been blocked anyhow.
In the case of the latter, it's good to look at the message log to see if any leaked through and ascertain why.
So it's a warning more than a severe alert. Keep an eye out.