I am using a simple flow to try and send email reminders out to clients one week before a due date. The loop is functioning correctly to bring back a list of records to email, but the email alert is failing with "insufficient access rights on cross-reference id". There is no write occurring during the flow, it is simply Get Records -> Loop -> Email Alert. I have ensured that the email template is in a shared folder and have tested it in a public folder as well. The flow user is the System Admin account and should have full access to the custom object I am referencing. The recipient email address for the Email Alert is an email field on the custom object. For testing I have kept the email template static, without merge fields. This is my first attempt to send emails from production, so perhaps there is a problem with the setup from that side, but I have set the myself as the Default Workflow User and the Automated Process User Email Address as mine, for testing. I have tested email deliverability successfully. I have done a fairly exhaustive search for solutions and been unable to find anything.