Resolving Permission Denied error when using iGrafx Data IO (IDIO)

Problem

When trying to import or process data using iGrafx Data IO (IDIO), you may experience permission problems and see the following dialog:

There are various issues that can cause this type of error. The below list contains some of the more common issues that can result in this dialog

The user you are attempting to access the platform with has no API key configured. This can be verified by opening their Administration → User Management and finding the respective user. Click Edit . If there is a Generate API Key button, the user does not currently have an API key. Click the button to generate and use it.
The API key you are using is incorrect. There is no way to confirm the validity of an API key after it has been generated. A solution is to generate a new key via Administration → User Management and finding the respective user, then click Edit . Click Delete API Key and then generate a new API key
This will make the previous key unusable and you will have to make sure the key is not used in any other API integrations, or update the key there as well with the newly created one
The REST API is not enabled or the respective authentication type is not allowed. This can be verified by going to Administration → Support → REST API . On the page, ensure both Enable API and Allow access via API Key are both checked
The user does not have the Access REST API server level permission. To check this, go to Administration → User Management and find the respective user. Then click Edit under Server Roles on the right side, check which server roles the user receives and make sure at least one of them has the Access REST API permission allowed. This can be checked under Administration → Security Roles → Server Roles