we are using Office 365 and Mimecast for Email-security&backup. recently all the Office 365 admins started receiving mail notifications with the same subject line. the mail details are below..
HTML Code:
Subject: "Phish delivered due to an IP allow policy"
severity: "Informative"
Activity: "Protection"
details: "1 message hit on xxxxxx-xxxxxx-x, sent by some.user@company.com to some.user@company.com at time month/date/year time."
Please suggest me what shall we have to do to mitigate this issue. frequently receiving such notification mails will certainly grab attention and expecting this to lead some serious problem. please help me the steps which should I take!