Hi Leticia,
Sorry for the inconvenience the problem caused for you.
Based on your description, you keeps receiving an error about Microsoft AutoUpdate.
Since you are using the latest version, we’d also suggest you refer to the steps we provided above to renew the app to check if the same problem will occur.
- To renew the MAU(Microsoft Auto Update), you could open Word for Mac then click Help > Check for updates to launch MAU, right-click the icon on the Dock > Options > Open in Finder, then delete the file.
- After that, go to /Library/Application Support/Microsoft, delete the folder Microsoft AutoUpdate.
- At last, you could download the latest MAU from this page: MAU release history.
Additionally, I found a thread which has the similar issue with you, and members provided the solution in it, you can try them out: Install verification failed - Microsoft Community
Additionally, please provide screenshots of the detailed version number(including build number) of your Mac OS version and Office version.
Best regards,
Jazlyn