When trying to pull in .xlsx files error message "Failed to connect to database and underlying database error occurred class not registered". Windows 11 Pro
Are you getting this error in ArcGIS Online (since the thread is posted in ArcGIS Online space)?
In case it is ArcMap or ArcGIS Pro, let us know the version.
I am having the same issue on Windows 10 ArcMap 10.8.2
