I am trying to send Email using email sending software through smtp server

But I am getting this Error.

The message could not be sent to the SMTP server. The transport error code was 0x80040217. The server response was not available
we use 2 other email accounts but the same problem

any one having any idea about it please Help me.
Thanks

Double check that your credentials are correct. I've seen this happen when the password expires or is changed.

you mean if we change a new password .
it's work.