Exchange Online - "Not recognized as a valid sender"


  • I can't send email; Outlook says I am "Not recognized as a valid sender"


  • Oregon State University
  • Employee, Student Employee, or Associate
  • Exchange Online


The most common cause of this issue is that Microsoft has blocked your email address for sending suspected spam.


Contact the Service Desk to resolve this issue.

If your account was actually compromised and sending spam email, your OSU account will be deactivated and you will need to reset your password. The Service Desk can assist with this process. Please note that it can take some time to resolve a compromised account issue.

If your account was not sending spam, Service Desk will ask the OSU Office 365 team to unlock your account.


For assistance, contact the Service Desk.


Article ID: 103429
Fri 3/27/20 12:11 PM
Tue 9/1/20 3:33 PM