Hi,
Could you provide the detail error message about the security dialog box?
You can upload the picture here by post an answer (Please Note: the Max size is 3MB for the picture):
I also suggest you refer to this support article:
You can also try to remove Office for Mac completely and re-install it to troubleshoot the problem:
Please be a bit more precise to explain your problem or you can upload a screenshot so that I
If the response is helpful, please click "Accept Answer" and upvote it.
Note: Please follow the steps in our documentation to enable e-mail notifications if you want to receive the related email notification for this thread.