Outlook suddenly only opening in browser

I’ve been using Office 365 for a while and everything has been working fine. Then yesterday morning Outlook suddenly would only open in Edge. I couldn’t get the Outlook app to open with the only option for the app being “open in browser.”

The only thing I can think of that’s different is I recently deleted some cookies from Edge, but, IIRC, they all had names like “adtracker.” Definitely nothing like “Microsoft” or obvious like that.

Any help on how to get the Outlook app working again would be greatly appreciated.