Payables Workflow error for InvoiceApprovalRuleSet

Summary:

I'm trying to set up a new Regional Finance Director for invoice approvals. The manager was reviewing and approving invoices as a regular manager and has been with the company for over 20 years. I have never had an issue before, it's seems pretty straight forward. I can make the configuration set up without issue but when I test to try and send an invoice, I get this error message below. Where should I look to try and resolve this?

Content (required):

The rules defined under rule set InvoiceApprovalRuleSet didn't return any results. (FUN-720336)

Cause Probable causes includes a participant doesn't have any active rules, no matching rule exists, the rule definition is incorrect, or none of the rules evaluates to true.