How to set a default browser to open links in the NEW Outlook app
If you are on the New Outlook app, on the right side of the top ribbon, slide the slider to the left to switch to the old Outlook app.
After the Outlook app restarts, on the top ribbon click on File.
Next, click on Options.
On the left pane, click on Advanced and on the right pane, click on drop menu for Open hyperlinks from Outlook in: and select Default Browser if Microsoft Edge is selected. Click on Ok button to close Outlook Options.
On top right of the Outlook app ribbon, slide the slider to the right, to switch back to the new Outlook app.
