To make sure that your recurring invoices are sent directly to the customer, please change your account's settings by following the instructions below:
1. Click the Settings tab.
2. Under Preferences category, click the General Preferences link.
3. In the General Preferences page, under Recurring Invoice section, select No, send it directly to my customer. I dont want to review it before sending it out.
4. Click the Save button.
From now on, all your recurring invoices will be automatically sent to the customers.
Zoho Invoice FAQ