535 5.7.8: authentication credentials invalid
The username or password you gave the SMTP server was rejected.
Rejected by policy or reputation
What 535 5.7.8 means
The server received your login but did not accept it. Common with providers that require an app password or have disabled basic password login.
Common causes
- A wrong or changed password
- Two-factor authentication requiring an app password
- Basic authentication disabled by the provider
- The wrong username format (full email address versus plain name)
How to fix it
- Re-enter the credentials
- Create an app-specific password if your provider requires one
- Check the provider's SMTP settings page
What to do with the address
Unrelated to the recipient address.
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 535 5.7.8 mean?
- The username or password you gave the SMTP server was rejected. The server received your login but did not accept it. Common with providers that require an app password or have disabled basic password login.
- Is 535 5.7.8 a hard bounce or a soft bounce?
- Rejected by policy or reputation. It is usually about the sender, not the recipient.
- What should I do with the address after 535 5.7.8?
- Unrelated to the recipient address.