This error occurs when the API key you are using is not authorized to perform the requested action.
To resolve this error, you can create a new SendGrid API key and select "Full Access" to provide access to all parts of your account using the API key or decide the permission scope based on your requirements.
Figure 01- Creating a new SendGrid API key
SendGrid allows you to scope permissions on three levels: Full Access, Restricted Access, and Billing Access. Granting "Full Access" will resolve this error.
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