Fix the ‘unknown recipient’ undelivered email error
Definitions
The ‘unknown recipient’ undelivered email error means the email address you’re trying to send to doesn’t exist or is incorrectly spelled. The email address you send to is called the recipient email address.
Before you start
✅ This error is always related to the recipient’s email address, never your email service.
ℹ️ You can fix this email error in a few seconds on your own.
Step by step
1. Check for typos on the recipient email address
Verify your recipient’s email address. It’s easy to mistype an email address, especially if it’s a long one. Check for any spelling mistakes or incorrect domain names (like ‘gnail.com’ instead of ‘gmail.com’).
2. Check the recipient email address exists
Confirm with your recipient their email address exists. Sometimes people give out old email addresses or you have outdated contact information. Double check the email exists and can receive email.
3. Check if the recipient mailbox is full
Sometimes this error can get triggered because your recipient’s email mailbox is full. The recipient has to clear their mailbox to receive new emails. If you can text or call them, let them know their inbox is full and they need to clear it so they can receive email from you.
4. Send to a different email address
If the error persists after trying the fixes above, the recipient’s email service may be the issue. Ask them for an alternate email address to use while they resolve it.