The typical cause for this error is when the recipient's spam filter blocks emails sent by the sender. However, it may even be due to the configuration made on the SPF record that denies or adds specific domains to blocklists.
The resolution for this issue is relatively straightforward; the sender may need to reach out to the recipient to check the email spam or blocklists and remove any entries of the sender's domain.
As a permanent solution, it is always encouraged to adhere to email best practices and avoid sending attachments that identify as spam or malicious.
View all errors