I\'d like to use a service account to access a Google Sheet via the Apps Script Execution API, but it\'s not clear from the documentation whether this is supported.
Your problem is probably that the script is associated with the wrong project (i.e. its own project, instead of the project associated with your Service Account). Here is what you need to do:
From the Scripts editor select the following menu item: Resources > Developer Console Project.
On this screen enter the project number for your dev console.
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