Email Delivery Issues
When emails fail to reach your customers, PayRequest’s bounce suppression system kicks in to protect your sender reputation. This guide helps you understand why emails bounce and how to resolve delivery problems.PayRequest uses Resend for email delivery and automatically tracks bounces, complaints, and failures via webhooks.
Common Bounce Reasons
| Error Message | Meaning | Fix |
|---|---|---|
550 5.1.1 ... does not exist | Email address doesn’t exist | Ask the customer for their correct email and update it |
550 5.2.1 ... mailbox full | Recipient’s mailbox is full | Wait and retry later, or contact the customer via other channels |
421 ... temporarily unavailable | Server is temporarily down | Usually auto-resolves — the Failed status will clear on next successful delivery |
User marked as spam | Customer clicked “Report Spam” | Contact the customer directly to resolve; they may need to whitelist your address |
How to Fix a Bounced Customer
Go to the customer profile
Navigate to Customers and click the affected customer. A red Email Delivery Blocked warning appears at the top.
Check the bounce details
The warning shows the bounce type, date, and SMTP error message. Use this to determine whether the email is permanently invalid or temporarily unreachable.
Fix the email address
If the address is wrong, click Edit Customer and enter the correct email. This automatically clears the suppression and removes any “Invalid Email” tags.
Finding Affected Customers
Use the Email Issues filter on the customer list to quickly find all customers with active bounce or complaint issues:- Go to the Customers page
- Open the Status filter dropdown
- Select Email Issues (only appears when issues exist)
- Customers with active suppression show a red Bounced badge
Preventing Bounces
- Validate emails at entry — Use proper email validation on your shop checkout and customer forms
- Monitor the Email Issues filter regularly to catch and fix bounce issues early
- Keep contact info updated — Ask customers to confirm their email when they log into the portal
Delivery Confirmation
PayRequest tracks when Resend confirms delivery of invoice reminders. Look for the green Email Delivered event in the invoice timeline to verify a reminder reached the customer. If a reminder shows as sent but never shows a delivery confirmation, the email may have been silently dropped by the recipient’s mail server (e.g., caught by a spam filter without generating a bounce).Next Steps
Email Health & Suppression
Full guide to the bounce suppression system
Payment Reminders
Configure automatic reminder schedules