How to merge Zoho Inventory into CRM

How to merge Zoho Inventory into CRM

We have an account that has made purchases from us and we have their sales orders in Zoho Inventory but in Zoho CRM it does not show any sales orders. All it is showing is "Error while retriving data from Zoho Books". Would there be a way to merge the info so that we know on the CRM that they have made purchases?