Emails bounce back from Outlook, not from Comcast - Microsoft Community

first, sent out email distribution list=contact group contained 60 addresses.

10 bounced back.  of addresses correct.  when sent 1 message each of 10 using address book, 1 went through, no bounces.

except one.

that 1 keeps bouncing.  details folder attached has message:

diagnostic-code: smtp; 554 5.7.1 [p4] message blocked due spam content in message.

the message contains no attachments, short message in body. 

i sent message via comcast website, , seems have gone through.  has not bounced yet, on 20 minutes, assume not bouce back.

first, why did original 10 bounce? 

second why 1 message bounce?

this has never happened me before; have used outlook since 1999. 

note on drop down menus under email:  don't think there microsoft office 365 home.  have individual package 7 applications.

hi,

the reason of getting bounce email messages depend on error messages receive. need additional information below isolate concern:

• did receive error messages after getting 10 bounce emails?
• when did issue first occur?
• are using pop3, imap or exchange server settings on outlook app?
• does issue occur random email addresses?

receiving error smtp code 554 5.7.1 rejection recipient domain , might caused following reasons:

• there spam content detected in message.
• the ip address either blocked recipient or listed in blacklist.

do come required information , glad assist you.

Office / Outlook / Windows 10 / Office 365 Home