Link 3 SMTP From mail not required

When setting SMTP in Link 3 Partner/Locations, From email address is not required.
But not providing this results in the error:
[2024-10-15 08:14:49.474 UTC] [Error] [MailSender] - SMTP connection failed: Mailbox unavailable. The server response was: 5.1.8 From address not allowed - Exception: System.Net.Mail.SmtpException: Mailbox unavailable