501 5.1.3: bad recipient address syntax
The server could not parse the recipient address you gave it.
Permanent failure (hard bounce)
What 501 5.1.3 means
Like 553 5.1.3: a syntax error in the address. Often caused by angle brackets, quotes or display names in the wrong place, or an empty domain.
Common causes
- A malformed address
- Display-name formatting passed where only an address belongs
- Unicode or illegal characters in the address
How to fix it
- Pass the bare address (name@example.com) to the sending system
- Validate and clean addresses before sending
What to do with the address
Fix the formatting, or remove the entry if it cannot be repaired.
Check an address now with the free email checker, or look at a domain's mail setup with the email domain checker, MX lookup and SPF checker.
Related error codes
Frequently asked questions
- What does 501 5.1.3 mean?
- The server could not parse the recipient address you gave it. Like 553 5.1.3: a syntax error in the address. Often caused by angle brackets, quotes or display names in the wrong place, or an empty domain.
- Is 501 5.1.3 a hard bounce or a soft bounce?
- Permanent failure (hard bounce). The address will keep failing, so remove it.
- What should I do with the address after 501 5.1.3?
- Fix the formatting, or remove the entry if it cannot be repaired.