Custom SMTP: Failed to send mail: 501 Sender syntax error

[totnek]

Knowledge Drop

Last tested: Nov 30, 2020

When we see this error message on SMTP setting page, more likely to be due to incorrectly defined the "from" setting. User should insert an email address for "from" setting.　

ref:

• Email With Rails 3 and Heroku Net::SMTPSyntaxError: 501 Syntax error
• "Sender syntax error" in Chilkat4Xojo

This content is subject to limited support.