Delivery Status Notification (Failure)

Delivery Status Notification (Failure)

Hello,

i have got this message sometimes when i sent an email to my zoho mail account.

Address not found

Your message wasn't delivered to olivier@********ks.fr because the address couldn't be found or is unable to receive email.


Why ?

Also, i received an error from the SaaS i am using with this email (smtp/imap)

"Failed to receive greeting from server in required time"


any explanation ?

Best regards