Using classic Outlook for Windows in business environments
Dear OverFifty
Thank you for posting to Microsoft Community
I understand your concern, I noticed that the sender always starts with "preview@", may I ask how you set up the rule? I've done a test on my side, as shown in the picture below, may I ask if this is how you set up the rule? (As long as the sender address contains the word "preview", the corresponding email will be deleted), or would you like to share the screenshot of the rule you set up with me?
(This is the path to the outlook.com rule set)
Did you click the Synchronize button to make the rule effective after you set up the corresponding rule? If you don't click the Synchronize button, the rules you set may not be valid.
I wish you all the best
Linda.W-MSFT | Microsoft Community Support Specialist