The integration between FSM and Books can fail due to several reasons. The reasons and the resolution for these integration errors are explained in the below sections.

If taxes are enabled in FSM, they should also be enabled in Books. If the Sales Tax is disabled in Books, you will encounter an error while creating invoices. To enable tax in Books, navigate to Settings > Taxes and click Enable Sales Tax.

If the services and parts used in FSM that have been synced with Books are deleted, then the invoices containing these services and parts cannot be created.

If the Contacts/Accounts in FSM that have been synced with Zoho Books/Invoice are deleted, then the invoices containing these Contacts/Accounts cannot be created.