Microsoft 365 features that help users manage their subscriptions, account settings, and billing information.
Hi BH33,
Thanks for provide the details in your post. About your question, please kindly check following steps to see if it can help you fix this issue:
- In Exchange Admin Center, go to mail flow > rules and then click "+" to create a new rule.
- Then set the new rule like below picture:
Note: in step 4, please enter following code:
<p><div style="background-color:#FFEB9C; width:100%; border-style: solid; border-color:#9C6500; border-width:1pt; padding:2pt; font-size:10pt; line-height:12pt; font-family:'Calibri'; color:Black; text-align: left;"><span style="color:#9C6500"; font-weight:bold;>CAUTION:</span> This email originated from outside of the organization. Do not click links or open attachments unless you recognize the sender and know the content is safe.</div><br></p>
I have tested above rule on my side and I can successfully show the warning message(see below picture), if you have any problems when doing so, please feel free to post back and provide us a screenshoot of the detailed information about the rule you created for analysis.
Regards,
Jennifer