Problem with mails send

Hello,
Please I need your help for explain me what is happen with my eform snipped.
When I submit my quick form I have this menssage: "Main mail: Mailer was unable to send mailThe following From address failed: "
I changed the snipped eform for:

$mail->IsSMTP();

and add this code:
$mail->Host = "smtpserver";
$mail->Hostname = "smtpserver";
$mail->SMTPAuth = true;
$mail->Username = "login";
$mail->Password = "xxx";

because the email server requires authentication

Please can you help me

Please I need urgently resolv this problem
Can you help me

Are you sure that you have the SMTP server configuration correct. Need an account with a valid login to send via SMTP.

Yes I have, and I need the authentication....
I have some question....
The smtp is of the host where the website is accommodation or
the smtp of the reply email

The SMTP of the server sending the mail, this will be the host where MODx is installed.

I am the correct authentication...
I don’t understant why I don’t get send mails...

Note-> I can send mails, but I can not send to a expecific mail . Why can this be happening?

It sounds like there’s something wrong with the address you’re trying to send to.

But I tested sending an email from my account email and was received...

This email is a different host of the modx
and I know that this email need authentication

Why can this be happening?

This may be related to the SMTP host. It could be set to check if an address exists and it considered good before sending. If you can send to other addresses then I would guess that this is the problem.

and what do I do!!?

I know that this account email is working, because I tested....
but I don’t receive any email in this account from the quick form of the modx