The error message with the details "User doesn't have permission to access customer." can occur on the "Send Data" step when setting up your Zap, or in an errored Task in your Zap History.
The account selected in the "Use Google Ads As" field of this action does not have valid permissions.
The account selected in the "Use Google Ads As" field must:
- Approve Zapier as a data partner by going here on Google
- Be accessible by the Google Ads account connected on the "Choose account" step