Information Regarding Red Exclamation Mark in Emails

Hi all,
I was just testing email from 2 of my servers,
I noticed a red exclamation mark on one of my emails (Just beside the sender name). Can anyone explain what it is about. the screenshot is given in the following link.


It just denotes the presence of one of these MIME headers in the message header (usually X-Priority):

X-Priority: 1
X-MSMail-Priority: High
Importance: High

It means the sender marked the message as “High priority”. It is not authoritative in any way, and only signal the intent of the sender.