Publish & Add Web Part an Excel Spreadsheet in SharePoint

Add a trusted file location

1. Go to 'Central Administration' home page -> click 'Application Management' tab -> in the 'Office SharePoint Server Shared Services' section, click 'Create or configure this farm's shared services', You're in the 'Manage this Farm's Shared Services' Page.
   
   
2. Click 'SharedServices1(Default)', it takes to the 'Shared Services Administration: SharedServices1' home page, in the 'Excel Services Settings' section, select 'Trusted file locations' and click 'Add Trusted File Location'.