Sometimes email is quarantined as spam from a sender that you routinely communicate with. The easiest method is to right click on an email you have received from that sender, select Junk from the menu, and then choose the option “Never block Sender”. This will add that email address to your Safe Senders list.
You can also add or manage your Safe Sender list in Outlook by clicking on Home, then Junk and finally selecting Junk Email Options. In the window that opens, you can select the Safe Senders tab to manage your personal allowlist. This is where you will be able to add a specific email address as well as remove any names that were added previously. Please note that adding entire domains is not supported at this time.
Note: Addresses added to this list will result in emails sent to you from those senders completely bypassing spam, spoof and phish filtering.