error on sending message

[Buckshotdesigns]

Unable to send message. Check sender, recipients and message body
Traceback (most recent call last):
File "/Users/bryanbuckus/Desktop/smtp-email-spoofer-py/spoofer/models/smtpconnection.py", line 97, in send_mail
self.server.sendmail(self.sender, self.recipients, message.as_string())
File "/usr/local/Cellar/[email protected]/3.9.0_2/Frameworks/Python.framework/Versions/3.9/lib/python3.9/smtplib.py", line 885, in sendmail
raise SMTPRecipientsRefused(senderrs)
smtplib.SMTPRecipientsRefused: {'[email protected]': (550, b'relay access denied - please authenticate')}