SMTP Error Code
Server says: 535 authentication failed (#5.7.1)
Solution for Server says: 535 authentication failed (#5.7.1)
A “535 authentication failed (#5.7.1)” error is usually related to the SMTP User Authentication details you have configured (or not configured) in your email settings.
Here are instructions to add or modify SMTP User Authentication details in GroupMail.
If you continue to have problems after adding or modifying the SMTP User Authentication details in GroupMail, contact the host of the mail server you are using to relay your email to explain the error and to confirm the details that you have entered.
As always, feel free to contact the GroupMail support team. They will be happy to help you to fix it.