App Expert Reply:
– You can see this error is referring to the Opportunity_View_URL field and this user does not have sufficient access to this field or Opportunity object.
– This specific error says the user has “read” access only to Opportunity object so they cannot generate a document successfully and edit that Opportunity field.
– To update sharing settings: go to your Setup > Security Controls > Sharing Settings > click “edit” and then change the sharing access to Opportunity to public read/write and also check access to document action object and document request object. Click to save.
– If you don’t want to fully open permissions to that user but have the document generation working under another admin user, you have the option of using app feature to have one admin user authorize the app with their google drive to force their authorization over other users and can see this article for more detail.