Dear Leann H,
Good day! Thank you for posting to Microsoft Community. We are happy to assist you.
It seems that the email you are trying to send is being blocked by your company's security policies. This could be due to the sensitive information contained in the email, such as the SS# and DEA#.
However, to better understand the issue and provide possible solution, we need more details from you, please kindly provide us the following information. Thanks in advance!
- May I please know if your company set any custom security policy or mail flow rule to prevent sending sensitivity information?
- May I please double confirm if this issue is only when you reply/forward to the email or when you also normally send the sensitive emails?
- May I please confirm if your tried to send the email without including the sensitive information in the subject line?
- Could you please provide us with the screenshot of the error message?
I look forward to your reponse. Kindly note that the above requested information is required for further analysis and troubleshooting of your situation. Your patience and cooperation are much appreciated.
Thank you for your precious time. Have a nice day.
Sincerely,
Libeamlak | Microsoft Community Moderator