Email Error: "Not Recognized as a Valid Sender"

This article applies to: Email for Faculty and Staff

This error message indicates that Microsoft has flagged your account as exhibiting spam-like behavior. See our Microsoft's Exchange Online Protection article for details and what to do about it.

Email for Faculty and Staff Articles

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Troubleshooting

Email Error: "Meeting Out of Date"

Office 365 users report seeing repeated notices of "Your meeting was found to be out of date and has been automatically updated." This message usually appears when a user accepts a...

Email Error: "Not Recognized as a Valid Sender"

This error message indicates that Microsoft has flagged your account as exhibiting spam-like behavior. See our Microsoft's Exchange Online Protection article for details and what to do about it...

Email Known Issue: Offline Address Book

It can take up to six hours for new entries to be added to the Address Book; the process that keeps everything in sync runs every six hours. In addition to affecting searches for contacts, this...

Email Known Issue: Persistent Forwarding Alert

When an email user has set up forwarding from an Office 365 account to an external address (typically set through Outlook on the web), Outlook on the web displays an alert every time the user...

Email Problem: Finding Messages Marked as Spam

This information applies to both faculty/staff and students. Even though students receive their mail through Google Workspace (formerly known as G Suite), the messages first pass through Microsoft's spam and virus filters.

Exchange Account Warning for iOS

What to do if you see the following warning, "Adding an Exchange account will allow the Exchange administrator to remotely manage your device. The administrator may collect personal data, add/remove accounts and restrictions, list, install, and manage apps, and remotely erase data on your device."

Fraud Detection Warnings on Email Messages

Overview You may have seen warnings on certain email messages, stating that the message's validity could not be verified. The examples shown above are two such ...

I Can't Download Microsoft Office Apps

Faculty, staff, and students all receive a Microsoft Office 365 license. Depending on your exact affiliation with the university, you have either an A1 or A3 license. Only A3 licenses can download...

Official Mailings and Third-Party Senders

Notes About Mailings Not From Cornell Organizational Mailings When sending email on behalf of a Cornell University college, unit, or any organization affiliated with the university, to...

Problem: Email from a Cornell Address Rejected or Refused

Sometimes we get reports that email sent from @cornell.edu addresses to external addresses (or forwarded from a Cornell address to an external address) is being rejected or having delivery refused...

Problem: Google Workspace Calendar Events that Pass Through Office 365

Microsoft is investigating an issue where calendar events that begin in Google Workspace Calendar, go to Office 365, and return to Google Workspace may not display properly in Google Calendar....

Problem: Message You Send Get Tagged as Spam

You may hear that messages you send are ending up in the recipients' Junk or Spam folders. If this happens to you, Go to your account in Outlook on the Web. (Launch Outlook on the...

Resources for Transitioning to Modern Authentication for Office 365

As previously announced, on October 1, 2022, Microsoft will permanently disable Basic Authentication (“Basic Auth”) for Office 365 Exchange email. Any accounts still configured or coded to use...

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Email Error: "Not Recognized as a Valid Sender"

Email for Faculty and Staff Articles

Troubleshooting

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