How to Export Table sql to Excel file in sql server 2014?
This may be a file permissions/uac issue. 

To prove/disprove that, create a new folder and copy (not move) the excel file into it, then give the windows security group "Everyone" Full control on the folder and its files. Update your export query with the new file location and try running it again.

If that works (or if you at least get a different error), then bear in mind that wherever you want to have the export file in the end, the file will need read/write permission assigned for the user account your SQL Server service runs under. (Or the "Everyone" group, but that wouldn't be best security practice.)