How to see which recurring invoice a project is associated with

How to see which recurring invoice a project is associated with

I have four projects that are giving a sync error with Zoho Projects. "Once a project is invoiced, the customer associated with that project cannot be changed." All the time is unbilled for each of these projects. I think this error is because they are related to a Recurring Invoice. We have 100s of recurring invoices. How do I find out which recurring invoice is associated with these projects?