Hi @Betty Stolwyk
Glad to hear this issue has been resolved and thanks for the sharing!
However, due to a recent update in forum policy, the question author now is not able to accept their own answers.
So, I have written a brief summary of the solution this issue. Please feel free to ACCEPT it as the Answer, which would benefit others who also have similar issues in the forum.
Issue:
Got the "This app can't open" error message when trying to open New Outlook.
Solution:
Open by going to Press Win+R>entered olk.exe
>Run command>This should open the New Outlook, close it and reopen it.
More information: Problems switching to New Outlook - Microsoft Community