SAFE LINKS
When a message contains a clickable image or text, the original address of the link will be replaced with a “safe link.” Safe links apply to ALL email sent to AEL, external or internal.
Safe links contain the string "safelinks.protection.outlook.com/" near the beginning of the URL.
Safe links, whenever possible, will show you the original URL when you mouse over the link. If the original content cannot be displayed, it will show you the safe link that your browser will actually use if you click on the message.
SAFE ATTACHMENTS
When a message contains one or more attachments, the message will be delivered and ATP will begin scanning the attachments. You can read the message body immediately, but the attachments won't be completely available until the safety scan is complete. You may, however, preview attachments deemed "safe" before scanning is complete.
If you open a message immediately after it appears in your Inbox, you might see the attachments listed as being scanned, as shown here. (Opening the "ATP Scan In Progress" attachment shows a message that explains the attachment sent to you is still being scanned.)
Safe Attachment scans typically complete in under 2 minutes, but they could take longer for large attachments. To see if the scan is complete, close and re-open the message.