Microsoft SharePoint 2013 builds upon previous releases in 2007 and 2010 to better support big data, mobile users and public-facing websites. Today we will describe about “Excel Services for SharePoint 2013 does not load workbook“. On a SharePoint also called a “Next-Next-finish” when trying to open a workbook in the browser with or without Excel Services developers are receiving this error:
To intention this issue, the Sharepoint Global Farm Administrator must grant access to the account to run the Excel Services Application. To do this, take after these steps for each one Web application:

Click Microsoft SharePoint 2010/2013 Products.
Click SharePoint 2010/2013 Management Shell.
At the Windows PowerShell command prompt (PS C:\>), type the following command, and then press ENTER:
PS> $w = Get-SPWebApplication –Identity <URL of the Web application>PS> $w.GrantAccessToProcessIdentity(“<insert service account>”)
Then, the service account is granted db_owner access to the SharePoint content database.
POWERSHELL
Find the site where you get the error and find the WebApp Name. If you are a SharePoint Global Farm Administrator navigate to :
Now, you must execute the first command line as demanded on the Support of Microsoft.
$w = Get-SPWebApplication –Identity . Now we must search the account that is being configured for Excel Services. Therefore please navigate to Central Administration > Security > Configure Service Accounts > from the first dropdown, select the application pool running “Excel Services Application” and get the Managed Account.
Our second command line as demanded on the Support of Microsoft looks like: $w.GrantAccessToProcessIdentity(“Domain\ManagedAccount”)
Click Microsoft SharePoint 2010/2013 Products.
Click SharePoint 2010/2013 Management Shell and execute the two following lines.
NON-POWERSHELL
If you can’t use PowerShell but you still have the issue there is another way to fix it.
Connect to your SQL Server and expand Security > Logins and find the Managed Account that is being used for the Excel Services.
under the properties Navigate to the User Mapping Page and select the Content Database of your Web Application where you get the error and add the Managed Account as a DB_Owner.