Thank you very much for your great explanation

Verify that you have the following administrative credentials:

You must be a member of the farm administrators group.

On the Central Administration Home page, in the Application Management section, click Manage service applications.

Select the Excel Service service application proxy you want to delete.

On the ribbon, click Delete.

In the confirmation dialog box, click OK.

Now we are going to make sure Excel services connectivity:
Go to central admin , system settings, manage services on server. You need to start the Excel Services and the Secure Store Service:

Using Powershell, recreate the Proxy
New-SPServiceApplication

Please let me know if this helps

I am following the same steps. The excel service get create but actually th eexcel proxy remains as stopped. I can’t connect it or start it.
do you have any solution to this?
i would really appriciate any help.
Thanks