Office 365 Safety Tips
Microsoft has implemented new functionality in Office 365 referred to as "Safety Tips". Safety Tips are intended to alert users of e-mail delivered to their mailbox that could be spam, a phishing attempt, or potentially fraudulent. An example Safety Tip is shown below and Safety Tips are explained in detail at Understanding Safety Tips in Office 365.
Example safety tip viewable in Outlook or the O365 Portal:
Users are advised to pay attention to information conveyed via Safety Tips and to either ignore or delete any e-mail they have concerns about. In some cases, safety tips will appear on e-mails that are legitimate, such as for messages delivered to a CSU user by way of a forward configured on an external e-mail account. Messages sent via listservs are also more likely to include safety tips due to the way messages are sent on behalf of a sender to the listserv members. In such cases, users can simply ignore the safety tip presented in an e-mail.
Safety tip functionality cannot be disabled. Also, due to the varied nature of what flags a message with a safety tip, there isn't a viable method available to mark a particular sender or type of message as "safe" so that future e-mails from the sender don't include a safety tip.