okay, the email form works now, we can send and receive messages in both ends – form sender and receiver. it was the problem of host server blocked the SMTP access, so we talked with their team, and got it fixed.
but, we keep having this error message “Failed to send message”, even though the email did go through.
(this is done with SMTP enable function)
the successful sending message “Message Sent” appears on top, when i tried to turn off the SMTP, but the email doesn’t go through.