Zoho Books Invoice Emails Going to Spam

How to fix it

// try these in order, the most common fix is first

1. FIX 1Authenticate your sender domain

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   1. 01Add your business domain as the sender in Zoho Books email settings
   2. 02Add the DKIM (and SPF, DMARC) records Zoho provides at your DNS host
   3. 03Verify the domain
   Did this fix it? Yes No

2. FIX 2Use a custom SMTP relay

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   1. 01Go to Settings > Reminders and Notifications > Email Notifications
   2. 02Open Email Relay and add your own SMTP server (Google Workspace, Microsoft 365, etc.)
   3. 03Send a test invoice to a Gmail address
   Did this fix it? Yes No

3. FIX 3Simplify the email and tell customers

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   1. 01Try removing heavy signatures or images from the invoice template
   2. 02Ask customers to mark the email Not spam and add your address to contacts
   3. 03Share the customer portal link as a backup
   Did this fix it? Yes No

Symptoms

Customers say they never received invoices or reminders, emails show as sent in Zoho Books but sit in recipients' spam folders.

Why it happens

• C-01Sender address on a domain without DKIM
• C-02Sending through Zoho's shared servers with a free email address
• C-03Gmail and Outlook filtering changes reported from November 2025
• C-04Email signature or content triggering filters (single user report)

// this guide also covers

• zoho books invoice going to spam
• zoho books emails not delivered
• customers not receiving zoho books invoices

The same problem in other apps

All notifications, reminders & messages not sending guides →

• Xero Invoice Emails Not Delivered (Xero)
• Wave Invoice Not Sending (Wave)

Other Zoho Books errors

• Zoho Books Bank Feeds Not Updating
• Zoho Books Balance Doesn't Match Bank
• Zoho Books Online Payment Error (CP Codes)
• Zoho Books Bank Statement Import Error
• Zoho Books CRM Sync Not Working
• Zoho Books Sales Tax Not Calculating
• Zoho Books Free Plan Limits ($50K Revenue)
• How to Cancel Zoho Books Subscription